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Discover Science

Chemistry

TEXTBOOK

Discover Science: Chemistry
Textbook

Philippine Copyright 2012 by DIWA LEARNING SYSTEMS INC
All rights reserved. Printed in the Philippines

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Authors
Dino F. de Guzman earned his master’s degree in chemical education from the University of the Philippines–Manila. He
obtained his bachelor’s degree in biochemistry and post-baccalaureate degree in teaching education from the University of
the Philippines–Diliman. Mr. de Guzman is a licensed teacher and has taught science in Claret School, James K International
Education Center, and La Salle Green Hills. He was also a college lecturer at Polytechnic University of the Philippines.
Maria Elena G. Delos Reyes obtained her diploma in science education from Philippine Normal University and her cognate
in education and bachelor’s degree in chemistry, with distinction, from St. Scholastica’s College. She is also a licensed
professional teacher and a member of the Association of Science Teachers and Educators of the Philippines and of the
Philippine Association of Chemistry Teachers. Ms. Delos Reyes has taught science and health in grades 3 to 6 at St. Anthony
School. In high school, she taught integrated science, chemistry, and physics at Cavite School of St. Mark, St. Anthony School,
and St. Scholastica’s College–Manila. At present, she works as a home-based writer, editor, and transcriptionist.
Allen A. Espinosa is currently completing his thesis requirements for his master’s degree in chemistry education at the
University of the Philippines–Diliman. He obtained his bachelor’s degree in secondary education major in chemistry,
cum laude, from Philippine Normal University. Mr. Espinosa has taught chemistry at La Salle Green Hills, chemistry and
integrated science at Philippine Institute of Quezon City, and chemistry and physics at Saint Pedro Poveda College. At
present, he teaches at Colegio de San Juan de Letran and at De La Salle College of Saint Benilde. Mr. Espinosa is a member
of the Philippine Association of Chemistry Teachers.

Consultant
Claribelle J. Bautista finished her doctorate in philosophy in education and her master’s degree in teaching major in chemistry
from the University of the Philippines–Diliman. She earned her bachelor’s degree in education major in chemistry from
Mindanao State University. Dr. Bautista is a licensed teacher and taught mostly chemistry at the high school department of
Lourdes School of Mandaluyong, where she also served as a science coordinator and an assistant principal on academics. She
is the founding president of the Science Educators Association of Mandaluyong.

Preface
The 21st century is marked by numerous advancements in science and technology. With all these
advancements, it is necessary that you are equipped with the basic science and technological skills. This
book, Discover Science: Chemistry, is designed to help you acquire the skills you need in the 21st
century. As you read through the lessons and perform the given activities in this book, you will develop
your inventive thinking skills; global awareness; and personal, social, and civic responsibility, among
others.
This book, which has been carefully designed to better facilitate your learning, is composed of
the following components:
Word Up includes an activity (e.g., word maze, crossword puzzle, etc.) that introduces the
important terms you will encounter in the lesson.
Sci-Kick displays a comic strip of two characters named Isay and Kiko. These characters will
tap your imagination on how the science concept(s) to be learned is evident in real life.
CSI (Cool Science Investigation)/Try It Out! presents an experiment/exercise that allows
you apply the science concept(s) you have learned in the lesson.
Chapter Test includes a 15-item multiple-choice exercise that measures your understanding of
the science concepts discussed in a chapter.
Science Cares presents an activity that relates the science concepts you have learned in a
chapter to different issues concerning the environment and the society. This will make you realize
how your knowledge in science can help you become a better citizen.
Performance Tasks lists tasks that will allow you to apply what you have learned to various
fields of discipline.
IP Checkup monitors the progress of your investigatory project (IP) at the end of each unit.
A chapter in this book has been solely allocated for you to learn how to construct an investigatory
project.
Aside from the components given above, some lessons in this book include the following
additional sections:
Pinoy Science gives an example of a notable Filipino and his or her remarkable contributions
to science and technology.
Info Overload presents a science trivia related to the science concept discussed in the lesson.

May this book help you understand and appreciate chemistry better. Remember that most
scientific discoveries sprouted from a simple question or a little dose of curiosity. Keep on learning
and enjoying as you discover the nature of chemistry!

Table of Contents

Unit I The Building Block of Science
Chapter 1 Nature of Chemistry .......................................................................................... 2
Lesson 1 The Evolution of Chemistry.................................................................................................2
2 Chemistry: Its Role in Science, Technology, and Society ...................................................6
3 The Processes, Tools, and Techniques in Chemistry .........................................................14
Chapter Test .........................................................................................................................................30
Science Cares .......................................................................................................................................32
Performance Tasks ...............................................................................................................................32

Chapter 2 Measurement .................................................................................................... 33
Lesson 1 Importance of Measurement ..............................................................................................33
2 Significant Figures .............................................................................................................39
3 Scientific Notation..............................................................................................................44
4 Mass, Volume, Density, and Temperature ..........................................................................48
Chapter Test ..........................................................................................................................................54
Science Cares ........................................................................................................................................55
Performance Tasks ................................................................................................................................55

Chapter 3 The Methods of Science ................................................................................... 56
Lesson 1 The Scientific Process ........................................................................................................56
2 Investigatory Science Project .............................................................................................60
Chapter Test ..........................................................................................................................................71
Science Cares ........................................................................................................................................73

Chapter 4 Matter................................................................................................................ 74
Lesson 1 The Nature of Matter..........................................................................................................74
2 Classification of Matter ......................................................................................................79
Chapter Test ..........................................................................................................................................89
Science Cares ........................................................................................................................................91

Chapter 5 Understanding the Atom ................................................................................. 92
Lesson 1 The Road to Atomic Theory...............................................................................................92
2 Atoms, Isotopes, and Ions ................................................................................................101
Chapter Test ........................................................................................................................................108
Science Cares ......................................................................................................................................109
Performance Tasks ..............................................................................................................................109
IP Checkup .......................................................................................................................................... 110

Unit II The World of Chemicals
Chapter 6 The Periodic Table ......................................................................................... 114
Lesson 1 The Development of the Periodic Table........................................................................... 114
2 Electron Configuration .....................................................................................................121
3 Groups and Periods in the Periodic Table ........................................................................134
Chapter Test ........................................................................................................................................143
Science Cares ......................................................................................................................................144

Chapter 7 Chemical Bonding ............................................................................................ 145
Lesson 1 Bond Formation and Molecular Geometry ......................................................................145
2 Molecular Geometry ........................................................................................................157
3 Chemical Nomenclature...................................................................................................165
Chapter Test ........................................................................................................................................169
Science Cares ......................................................................................................................................170

Chapter 8 Chemical Reactions ......................................................................................... 171
Lesson 1 Chemical Equations .........................................................................................................171
2 Stoichiometry and Other Calculations .............................................................................181
Chapter Test ........................................................................................................................................194
Science Cares ......................................................................................................................................195
IP Checkup ..........................................................................................................................................196

Unit III Gas, Solid, and Liquid
Chapter 9 Gases ................................................................................................................. 200
Lesson 1 Properties of Gases...........................................................................................................200
2 Gas Laws ..........................................................................................................................205
Chapter Test ........................................................................................................................................219
Science Cares ......................................................................................................................................221

Chapter 10 Solids and Liquids .......................................................................................... 222
Lesson 1 Nature of Solids and Liquids ...........................................................................................222
Lesson 2 Phase Change ...................................................................................................................229
Chapter Test ........................................................................................................................................233
Science Cares ......................................................................................................................................235

Chapter 11 Gases, Solids, and Liquids in Mixtures ........................................................ 236
Lesson 1 Nature of Solutions ..........................................................................................................236
2 Colloids ............................................................................................................................247
Chapter Test ........................................................................................................................................255

Science Cares ......................................................................................................................................257

Chapter 12 Aqueous Solutions .......................................................................................... 258
Lesson 1 Oxidation-Reduction Reactions .......................................................................................258
2 Acid-Base Reactions ........................................................................................................269
Chapter Test ........................................................................................................................................282
Science Cares ......................................................................................................................................283
IP Checkup ..........................................................................................................................................284

Unit IV Applications of Chemistry
Chapter 13 Introduction to Nuclear Chemistry .............................................................. 286
Lesson 1 Radioactivity ....................................................................................................................286
2 Nuclear Transformation ...................................................................................................297
Chapter Test ........................................................................................................................................300
Science Cares ......................................................................................................................................302

Chapter 14 Introduction to Organic Chemistry ............................................................. 303
Lesson 1 Nature of Organic Compounds ........................................................................................303
2 Hydrocarbon Derivatives .................................................................................................314
Chapter Test ........................................................................................................................................321
Science Cares ......................................................................................................................................323

Chapter 15 Introduction to Biochemistry ........................................................................ 324
Lesson 1 Biomolecules....................................................................................................................324
2 Metabolism.......................................................................................................................337
Chapter Test ........................................................................................................................................339
Science Cares ......................................................................................................................................341

Chapter 16 Chemistry in Daily Life ................................................................................. 342
Lesson 1 Food Chemistry ................................................................................................................342
2 Industrial Chemistry.........................................................................................................347
Chapter Test ........................................................................................................................................351
Science Cares ......................................................................................................................................352
IP Checkup ..........................................................................................................................................353

Glossary ..........................................................................................................................................355
Bibliography .......................................................................................................................................357
Index ..........................................................................................................................................359

The Building UNIT

Block of Science I

H ave you ever wondered what makes up the things that you use every day such as
your clothes, perfume, lotion, pens, and books? Do you want to know how fuel
makes power plants and cars run? Do you want to investigate how
medicines, ice cream, and sandwich spread are made? Do you want to know what makes up
paint, insecticides, air fresheners, and fertilizers? Perhaps, you are fascinated with the advanced
technologies used in forensics, medicine, research, sports, and communication. All of these involve
chemistry—the building block of science.
This unit invites you to take a look at and experience the wonderful world of chemistry. You
will discover how chemistry began and developed to improve the quality of people’s lives. You will
learn why chemistry can be considered the building block of all sciences, including biology, physics,
and geology. You will be trained to work like a real scientist. You will realize the significance of the
development of atomic theory to the technology you enjoy today.

Chapter 1
Nature of Chemistry
In this chapter, you will be able to
• trace the historical development of chemistry;
• recognize significant contributions of some Filipino and foreign chemists;
• explain how chemistry influences science, technology, and society;
• explain the nature of different types of matter;
• practice safety precautions in using different laboratory apparatus during experiments;
• apply rules of significant figures in solving measurement problems;
• plan an investigatory project that entails precise and accurate gathering of data; and
• appreciate the importance of chemistry in daily life.

Lesson 1 The Evolution of Chemistry

Word Up
Fill in the missing letters to find the term that each statement describes.
1. P __ __ __ __ __ A – It is the appropriate combination of ingredients that would cure all diseases.
2. A __ __ __ __ __ Y – It is a predecessor of chemistry.
3. E __ __ __ __ R of L __ __ E – It is a substance thought to bring immortality.
4. M __ __ __ __ __ __ __ M – It is a belief in communication and union with a divine being.
5. C __ __ __ __ __ __ __ __ N – It is a process in which fuel reacts with oxygen to produce heat,
light, and flame.

Sci-kick

Do you have any idea why we I think it’s because I guess you’re right! And chemistry
live in a modern world today? of the advancement is one of the reasons why
of technology. technological advances continue.


Chemistry can be traced back to as far as the prehistoric times. Its history and development can be
divided into four periods: black magic, alchemy, traditional chemistry, and modern chemistry.

Black Magic
The period of black magic covers the prehistoric
times until the beginning of the Christian era. The
ancient people lived in a rough environment where
they needed to protect themselves and to find ways of
procuring their sustenance. They tried to survive by
using what they knew. They discovered how to light
a fire even without knowing the chemical principle
involved in it. The discovery of fire significantly
shaped the early people’s curiosity in controlling
chemical changes. People soon found that applying
fire to food could change its texture and taste, and that
mixing fire with mud could produce hard substances
that can contain food. This was how ceramics was
Fig. 1.1 Ancient people learned to use fire to
discovered and developed during the Stone Age, the
cook food.
period prior to 8000 BCE.
Ancient civilizations were interested in metallurgy, pottery, and dyes. These crafts were
successfully developed in Egypt and Mesopotamia. The discovery of gold in 6000 BCE and copper in
4020 BCE were important breakthroughs in metallurgy. By 2000 BCE, people were producing bronze
by heating copper and tin ores together. Bronze was a strong enough material to be used in weapons.
Hence, this period is known as the Bronze Age. Around 1500 BCE, the Iron Age emerged when
people learned to extract iron from its ore by applying more heat. Iron would combine with carbon
during the process, strengthening it and producing steel, a malleable and strong alloy. By 900 BCE the
Egyptians were already experimenting with other forms of chemistry, particularly the mummification
or the preservation of human bodies with pigments and natural juices.
The Greek philosophers first formulated the basic ideas of element and compound from 500 to
300 BCE. Empedocles introduced a theory that all matter is made up of four elemental substances—
earth, air, fire, and water—in different proportions. Democritus believed that all materials are
made up of indivisible, indestructible, and infinitely small particles which were grouped together
in different proportions to form the different materials. He called this indivisible particle atomos,
which gave birth to what is presently
called atom. Aristotle supported
Empedocles’ idea of four elements
and Democritus’ idea of the atom. He
suggested that there were two pairs
of options—hot and cold, moist and
dry—which provided the exact nature
of matter. He described earth as cold
and dry, air as hot and moist, fire as
Empedocles Democritus Aristotle hot and dry, and water as cold and
moist.
Fig. 1.2 The Greek philosophers

The Building Block of Science

Alchemy
When Alexander the Great established the Roman Empire, ideas from the Greeks and those from
the Egyptians came together and were transferred to the Empire. The Arabs came in the 7th century
and started al-kimiya. The goal of al-kimiya was to find the following:
a. panacea – the appropriate combination of ingredients that would cure all diseases;
b. aliksir (later called elixir) of life – the secret potion that would allow a person to be immortal;
and
c. a way to transform base metals (lead) into gold using the philosopher’s stone.
Knights who had joined the crusades brought home the knowledge of al-kimiya from the Arabs to
the Europeans. Soon al-kimiya became known as alchemy which some Europeans took up. Despite its
growing popularity and use, alchemy was steeped in mysticism and culture that people found it hard
to establish the science behind the perceived magic or sorcery. The absence of a defined scientific
method made alchemy thrive for a long time.
In the 1500s, alchemy was integrated to medicine with the onset of iatrochemistry, in which
chemical knowledge was used in treating diseases. Unfortunately, iatrochemistry was still far from
the modern chemistry as people today know it because those who practiced iatrochemistry failed to
present findings based on a logical scientific experiment. Despite their efforts, alchemists were never
able to transmute cheap metals into gold or found the elixir of life.

Try It Out!
Getting to Know the Alchemists
Alchemy has been presented in popular media such as animation and films. Alchemists are
often depicted as sorcerers and druids who have magical or supernatural powers. In this activity,
you will gain awareness of how alchemists are depicted in several countries.
Use science books, encyclopedia, or the Internet to research three alchemists from three
different countries. Based on the information you have gathered, create a fictional alchemist.
Illustrate your alchemist and make a character profile. The character profile may be in the form
of a biodata or narrative.
Answer the following questions to guide you in making the character profile of your fictional
alchemist.
1. What is the name of your alchemist? 7. What are his or her current alchemy
2. What is his or her gender? projects? Discuss the tools, chemicals,
3. What is his or her nationality? and processes used by your alchemist.
4. How old is he or she? 8. What are his or her discoveries
and inventions related to alchemy?
5. What is his or her physical features?
Describe briefly his or
6. What is his or her overall personality? her discoveries and inventions.


Traditional Chemistry
The period of traditional chemistry, also known as primitive modern chemistry, covers the end
of the 17th century until the mid-19th century. It is a period of transition from alchemy to modern
chemistry.
In 1661, Robert Boyle published his book The Sceptical Chymist (The Skeptical Chemist),
which focused on the importance of the scientific method. When the scientific method was defined
and practiced, it paved the way for experiments and investigations on many scientific queries and
problems. This was such a defining period for chemistry. For this, Boyle has been regarded as the
father of chemistry.
The scientific method was very useful in proving or disproving certain theories during the
early years of chemistry. Two German chemists Johann Joachim Becher and Georg Ernst Stahl
introduced the phlogiston theory which states that all flammable materials contain phlogiston, a
substance without color, odor, taste, or weight that is released in burning. When a substance is burned,
phlogiston was supposedly added from the air to the flame of the burning object. In some substances,
a product is formed.
In 1776, Antoine Laurent Lavoisier disproved the phlogiston theory. He
realized that the part of air that combines with substances as they burn was
oxygen, the name he gave for “dephlogisticated air.” He recognized the true
nature of combustion, discovered oxygen and hydrogen, made the first list of
all elements, introduced a new chemical nomenclature
(a system of names), helped construct the metric system, and wrote the
first modern chemistry textbook Traité Élémentaire de Chimie. The law
Fig.1.3 Antoine Laurent of the conservation of mass during chemical reactions was also based on
Lavoisier, the father of his discussions. This law states that the masses of the reactants are equal
modern chemistry to the masses of the products after a chemical reaction. With his numerous
contributions to chemistry, Lavoisier was considered the father of modern
chemistry.

Modern Chemistry
The period of modern chemistry covers the mid-19th century up to the
present. In the 1800s, the order and vital understanding of proportions and
standards in chemistry came about, causing chemistry to flourish.
Inspired by Lavoisier’s works, John Dalton, an English chemist,
meteorologist, and physicist, established his atomic theory, which led to further
Fig. 1.4 John Dalton
advancements in chemistry—the most significant of which was the creation
of the periodic table. The periodic table gave way to a universal classification
method of the elements.
Many discoveries soon followed such as those involving subatomic particles, chemical bonding,
and radioactivity and nuclear reactions. Chemistry has applications to almost everything even to the
human body. Constant investigations led to the modern atomic theory, new subatomic particles, and
applied chemistry. Technology continues to advance, making chemistry the science as people know it


Lesson 2 Chemistry: Its Role in Science, Technology, and Society

Word Up
Search the word puzzle for the different branches of chemistry listed below. The words may be
spelled forward, backward, horizontally, vertically, or diagonally. Use each letter only once. Then
look up the meaning of each word in a dictionary.
P W L F N T R O W C C F L A R
V H V A L E R U I R W O A M H analytical –
K C Y Y I I E N N Z N R C H K combinatorial –
G U X S A R A R K Q L E I N D
food –
H I P N I G O X G Y S N T P R
P H I V R C O T Q G W S Y S N forensic –
W C K O H M A B A X Y I L M K green –
V G N O L B P L I N Y C A P I
inorganic –
Q I S F X V P V S R I N N V Q
F C S J H H W O S K Z B A D N
medicinal –
M E D I C I N A L K B C M O Y organic –
Y A N C M P O C O R S K J O B
physical –
D V N S C K N P B Y Y P S F C
polymer –
K P R J V F K S L Z R M V U M
V U G R E M Y L O P I O V N Q

Sci-kick

Do you have any
idea how important
chemistry is to the
society?

I think chemistry goes hand
in hand with technology.
Without chemistry, we won’t
have the things that we have
today like my fave chocolate
drink and cake.


Science and Its Branches
Science has been defined by different people in different ways. Scientists, teachers, and students
have their own definitions. Can you give your own definition of science?
The word science originated from the Latin word scientia, which means “knowledge.” It is also
related to the Latin word scire, which means “to know.” From this, science may be described as
something that pertains to knowledge and the process of acquiring this knowledge. How does this
definition of science compare with yours?
Science is a very big body of knowledge that can be divided into several areas of interest. It can
be divided into three main branches: social sciences, mathematics, and natural sciences.
Social sciences study human society and social life. Mathematics studies the nature of numbers
and explains certain phenomena or situations by using mathematical models. Natural sciences study
everything found in nature and may be subdivided into physical sciences and biological sciences.
Physical sciences deal with the nonliving component of nature, while biological sciences deal with
the living component. Chemistry is a physical science that deals with matter.

Technology
The word technology came from the Greek word tekhne, which means “art” or “skill,” and logia,
which means “the study of.” Thus, technology may be defined as the study of an art or a skill. It is a
study of crafting or making things. It can be defined as the use of scientific knowledge or principles to
create things that will address people’s needs. It makes life easier and more convenient. Technology is
the application of science.
Technology can be classified into products and processes. A technological product is an object
or infrastructure that helps people in their daily tasks. Tools, machines, gadgets, and buildings are
technological products. A technological process is a system or a set of procedures that people can use to
enhance their skills and talents or to be more efficient in their work. Fermentation, food preservation, and
water purification are technological processes. Can you give other examples for each type of technology?
Ideally, technology should always benefit humanity. However, the disadvantages of some
technology may outweigh their advantages. Using such technology may be detrimental both to human
lives and the environment in the long run. Moreover, some people may use technology for personal
gains rather than for the common good.

Try It Out!
Modern Technology: Is It In or Out?
Research three technologies from three different countries. Complete the table below and
share it with the class.
Technology: _________________________
Creator Features Advantages Disadvantages Good or Bad Reasons


One of the technologies that have made
a great impact on many aspects of society Info Overload
and people’s daily lives is the computer.
People can now do many things that were Will there ever be a time when people are
not possible or quite difficult to do years replaced with artificial intelligence (AI)? With
ago without computers. Moreover, with computers continuously being improved, some
the availability of the Internet, there is a people may think that the day will come that AI
surge of information and global awareness. ultimately replace human beings. In chess, AI has
The use of Internet made communication been employed in creating a computer program
and interaction among scientists and named Deep Fritz, which defeated Vladimir
researchers faster and easier. They can Kramnik, a world champion in chess, in 2006.
share information with each other and seek Deep Fritz is an improvement of other chess
advice or assistance in research from each programs created in the 1980s and 1990s.
other. Can you give other advantages of The AIs for chess, which included Deep Blue and
the Internet? Deep Thought, have the word “deep” in their names
In your study of chemistry, you as influenced by the novel The Hitchhiker’s Guide
will appreciate the use of information to the Galaxy. In the novel, an ultimate thinking
technology. You may find the Internet computer named “Deep Thought” was made to
to be a great source of information and answer the ultimate questions on life, the universe,
a valuable tool in your study. However, among other things.
not everything you find in the Web is AI has raised ethical issues and has been a
true or accurate. Some Web content have topic of debate about the future of technology and
very little credibility, while some are society. The use of computers, machines, and
mere opinions. Thus, you must be able to robots with artificial intelligence has advantages and
evaluate the information that you obtain. disadvantages. But one thing is certain, AI can never
As a science student, you are mainly replace humans. Advanced technologies are
concerned with accurate and validated created by people to make their work easier
information and knowledge. and not to replace them.

Etymology of Chemistry
The word chemistry has a number of origins. It may have come from the Greek word khemeia,
which means “metalworking.” It may have originated from the Arab word al-kimiya, which can be
interpreted in several ways. Al-kimiya can be taken to mean Egyptian science, noting that Egypt was
called kem-it. It was during their conquest of Egypt that Arabs came to know this type of knowledge.
It may have originated from the Greek word khymeia, which means “the art of melting metals and
alloy production.” In 1530, Georg Agricola, a humanist, suggested to drop “al-” from the Arabic
word al-kimiya, and return it to its classical root chymia and chymista instead of the earlier alchymia
and alchymista. This was then adopted and translated in French as chimie; in German as chemie; in
Italian as chimica; and in English as chemistry.

Chemistry and Its Branches
Chemistry is a physical science that can be defined as the study of matter and its composition
and structure, the changes it undergoes, and the energy associated with these changes. It consists of
many specialized fields and interacts with all other areas of science. Hence, it is considered a central


science. It relates to many sciences that deal with nature, such as physics, biology, astronomy, and
geology. Since nature is made up of matter, then everything in nature may be explained and further
investigated using chemistry. Thus, chemistry can be integrated with all the other sciences, leading to
the formation of its different branches such as the following:
1. Inorganic chemistry – is the study of the chemical nature of the elements and their compounds
not containing carbon and that are not organic. Examples of such substances are minerals
found in Earth’s crust and nonliving matter.
2. Organic chemistry – is the study of compounds consisting largely of hydrocarbons
(compounds containing hydrogen and carbon), which provide the parent material for all other
organic compounds. Carbon is studied separately because of its unique sharing properties
which allow it to form rings and long branched chains, producing hundreds of thousands of
carbon-based molecules. Organic compounds are particularly important because they make
up the majority of compounds in living organisms.
3. Physical chemistry – deals with the application of physical laws to chemical systems and
chemical change. It is concerned with the role of energy in chemical reactions.
4. Analytical chemistry – deals with the qualitative and quantitative determination of chemical
components of substances.
5. Biochemistry – is the chemistry of living organisms and life processes. It is concerned with
the composition and changes in the formation of living species.
6. Geochemistry – is the application of chemistry to processes taking place on Earth, such as
mineral formation, metamorphosis of rocks, and formation and migration of petroleum.
7. Radiochemistry – is the study of the chemical effects of high-energy radiation and the
behavior of radioactive isotopes, atoms of the same element that vary in the number of
neutrons they have.
8. Macromolecular chemistry or polymer chemistry – deals with the chemical synthesis and
chemical properties of polymers.
9. Environmental chemistry – is the study of the chemical and biochemical phenomena that
occur in natural places.
10. Green chemistry – is the study of the design of chemical products and processes that reduce
or eliminate the generation and use of hazardous substances.
11. Electrochemistry – is the study of the reactions that can take place at the interface of an
electronic conductor and an ionic conductor (an electrolyte).
12. hotochemistry – is the study of the interaction of light and chemicals.
P
13. Astrochemistry – is the study of the composition and reactions of chemicals found in stars
and in space, as well as the interactions between matter and radiation.
14. Food chemistry – is the study of the chemical processes in food.
15. Medicinal chemistry – is the study of the applications of chemistry to pharmacology and
medicine.
16. Forensics chemistry – is the study of the application of chemistry to law enforcement. It
involves chemical analysis of substances that may have been used in a crime scene.
17. Combinatorial chemistry – is the study of synthesizing substances quickly and inexpensively
using innovative methods.


Chemistry in Everyday Life
Chemistry touches practically every aspect of your life. It is involved in your essential needs,
such as food, shelter, clothing, energy, and clean environment.
Everything in this world is made up of chemicals. Your body is made up of different elements
such as hydrogen, oxygen, carbon, nitrogen, and other elements. Your different body systems involve
different chemicals and chemical reactions. Digestion is a chemical process that helps your body get
the essential nutrients from the food you eat. These nutrients are carried by your blood to various
parts of your body to build new cells and produce energy for your daily activities.
Respiration is another chemical process by which glucose is broken down and oxidized to
provide energy. It also explains what happens to oxygen when you breathe and why carbon dioxide is
released when you exhale. It can be summarized in the following equation:
C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + energy
glucose oxygen carbon dioxide water
Recall how plants produce their own food through photosynthesis, a process important for the
survival of people and animals. Plants give off oxygen that people and animals need to live.
The chemical reaction of photosynthesis can be summarized by the following equation:
6 CO2 + 6 H2O + light energy → C6H12O6 + 6 O2
Can you think of other chemical reactions happening in your daily life?

Chemistry and the Society
Chemistry improves the quality of people’s lives in various ways. It provides people with
new products and processes to satisfy their needs and solve problems in health, resources, and
environment. Researches in chemicals led to the discovery and development of synthetic fibers,
paints, adhesives, drugs, cosmetics, electronic components, lubricants, and thousands of other
products. They also led to the development of processes, such as improved oil refining and
petrochemical processing that save energy and reduce pollution.
Researches on the chemistry of living things spur advances in medicine, agriculture, food
processing, and other fields. In medicine, advanced medical equipment and new drugs are constantly
being developed to provide more accurate diagnosis, monitoring, and treatment of diseases. These
include computed tomography (CT) scanners, magnetic resonance imaging (MRI) machines, positron
emission tomography (PET), and laser-assisted in situ keratomileusis (LASIK) surgical machines.
Chemists respond to the needs of the increasing human population. Agrichemists look for ways
to make crops more tolerant to certain pests and herbicides; improve the taste and color, and promote
longer shelf life of fruits and vegetables; and improve the quality of plants to yield more and better
crops.
The use of computers to analyze complex data opened the door to combinatorial chemistry. A
combinatorial robotic system can produce thousands or millions of compounds in a year against 100
to 200 compounds that traditional chemists can produce. Aside from sequencing of human genes and
production of new drugs, combinatorial chemists also now apply combinatorial chemistry to other
fields such as semiconductors, superconductors, catalysts, and polymers.

10 Discover Science: Chemistry

Today, many chemists specialize in specific fields, such as forensic and materials chemistry. A
forensic chemist analyzes pieces of evidence gathered from crime scenes. They run tests on a piece
of evidence and reach a conclusion based on the results of these tests. Identifying pieces of evidence
is an important part of the larger process of solving a crime. This helps solve crime faster and more
accurately. A materials chemist studies and develops new materials to improve existing products or
make new ones.

Try It Out!
Chemicals Everywhere
Identify at least three chemicals you can find in each place listed below. Write the uses of
each chemical.
C - church
H - ospital
E - nvironment
M - arket
I - ndustry
S - chool
T - ransportation
R - estaurant
Y - our home

Chemists and Their Tasks
Chemists are scientists who seek and apply new knowledge about chemicals. They are the
experts in chemical reactions, chemical products, and chemical processes. They conduct scientific
researches, analyze substances, and synthesize new substances. They are needed in other fields
such as engineering, medicine, education, business, culinary arts, nutrition, sports, and computer
technology.
Some of the tasks of a chemist are as follows:
1. Analyze different chemicals such as their physical properties, composition, structure, and
reactions using varied techniques
2. Design, develop, and customize different products and processes
3. Conduct tests and researches to determine the validity of a process or equipment and to
develop or improve new products
4. Prepare different chemicals for experiments, production of new materials, and other industrial
and research purposes
5. Communicate with other scientists to share information, seek advice, criticize research works,
and develop researches
6. Write research papers to have a record of study conducted for reference and further research

The Building Block of Science 11

Foreign Chemists
Many scientists have contributed to the development of chemistry. Perhaps you can contribute to
chemistry as they did especially if you decide to specialize in this field.

Jöns Jacob Berzelius
(20 August 1779 – 7 August 1848)
He formulated the law of constant proportions, which states that inorganic
substances are composed of different elements in constant proportions by weight.
He discovered the elements silicon, selenium, thorium, and cerium. He was
credited for originating the chemical terms catalysis, polymer, isomer, and allotrope.

Friedrich Wöhler
(31 July1800 – 23 September 1882)
He contributed to the development of organic chemistry by synthesizing urea
in the laboratory. He also discovered several elements.

Gilbert Newton Lewis
(23 October 1875 – 23 March 1946)
He contributed to the understanding of the covalent bond and chemical
thermodynamics.

Glenn T. Seaborg
(19 April 1912 – 25 February 1999)
He discovered 10 transuranium elements, namely, plutonium, americium,
curium, berkelium, californium, einsteinium, fermium, mendelevium,
nobelium, and seaborgium.

Roy J. Plunkett
(26 June 1910 – 12 May 1994)
He accidentally invented Teflon (the DuPont trademark name for
polytetrafluoroethylene or PTFE). Teflon is nonstick coated cookware.

Filipino Chemists
Here are some Filipino chemists and their respective contributions to chemistry:
Anacleto del Rosario
(13 July 1860 – 2 May 1895)
He studied producing a pure kind of alcohol from tuba of nipa palm.
He is regarded as the father of Philippine science and laboratory.

Julian Banzon
(25 March 1908 – 13 September 1988)
He researched on the different methods to produce alternative fuel.


Amando Kapauan
(4 July 1931 – 12 October 1996)
He focused on studying the effects of heavy metals in our environment.

Baldomero Olivera
(1941 – present)
He discovered cone snail toxins or conotoxins. He discovered ziconotide
(Prialt), a pain reliever used for chronic, intractable pain for people with
cancer, AIDS, or certain neurological disorders.

Try It Out!
An Interview with a Chemist
Ask your relatives and friends if they know a chemist working in the Philippines. If not,
search the Internet or look up a telephone directory for companies related to chemistry. Look for
a chemist and set up an appointment for a face-to-face interview, if possible. If not, get his or her
e-mail address and interview him or her via e-mail or chat. Supply the information listed below.
Share your work with the class.
1. Name
2. Age
3. Educational background
4. Name of company and location
5. Position and nature of work

Based on your interviewee’s responses, answer the following briefly.
1. Would you consider becoming a chemist someday? Why? ________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
2. What are the possible jobs offered to chemists in the Philippines? __________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
3. Are Filipino chemists contributing to our country’s development? __________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________


Lesson 3 The Processes, Tools, and Techniques in Chemistry

Word Up
Name each apparatus and write your answer in each box.

Sci-kick

What do you
have there with I’ve borrowed some tools.
you, Kiko? I have to finish my science
project at home.


Science Process Skills
As you study chemistry, you will need the same process skills that scientists use when they work.
Science process skills are the tools you need to understand the mechanisms of the material world. A
scientifically literate person uses them in solving problems, making decisions, and understanding
further the society and the environment. Developing these skills will allow you to think creatively and
critically and help you satisfy your curiosity.

1. Observing
Observation is the most fundamental of all
the processes. When you observe, you gather
information through the use of one or more of your
senses (or instruments that extend our senses):
sight, hearing, touch, taste, and smell. Observation
is influenced by your past experiences. It
often involves instruments and requires careful
recording and description. Surprising or
unexpected observations occasionally contribute
Fig. 1.5 A scientist working in the laboratory
new and important knowledge. The gathered
information or observations are called data or facts.
An observation may be qualitative or quantitative. A qualitative observation involves using
as many senses as possible. It describes an object, a situation, or an event using only words.
A quantitative observation makes use of numbers, as well as words, in the description of an
object, a situation, or an event. Tools or devices are used to measure the characteristic being
described.
Based on Figure 1.5, the scientist may have the following observations:

Qualitative Quantitative
1. Each test tube contains a small 1. There are five test tubes in the rack.
amount of liquid.
2. The first test tube contains a clear liquid. 2. The third test tube contains 3 mL of green ink.

2. Measuring
Measuring is comparing an unknown quantity with a known standard of reference.
Measurements are to be recorded systematically with labeled units of measure. They should be
precise and accurate. Length, volume, mass, temperature, time intervals, and force are common
quantities that are measured.

3. Inferring
An inference is an explanation of an observation in terms of a previous experience. Inferring
is a process skill which allows you to blend your unique interpretation with your observations. In
science, inferences about how things work are continually constructed, modified, and even rejected
based on new observations. For example, a student who observed a white spot on his or her black
shirt may infer that his or her mother used bleach in washing his or her clothes.


4. Classifying
Classification is the process of grouping or ordering objects based on observable traits.
Objects that share a given characteristic can be said to belong to the same set. Classifying
involves grouping objects, concepts, or events based on observable properties to show similarities,
differences, and interrelationships. Waste segregation is an example of classification.

5. Predicting
Predicting is forming an idea of a future occurrence based on observations and inferences. A
prediction may be used to generalize that under a certain set of circumstances, a certain outcome
may be expected. It may be used to describe outcomes beyond the observed data. For example,
you are collecting data on the temperature of water. If the readings are 30°C, 32°C, 34°C for 3
minutes, you can predict that after 5 minutes of heating, the temperature of water will be 38°C.
This is called interpolation. In interpolating, predictions are made within the range of given data.

6. Communicating
Communicating is the process of organizing and processing data using words, symbols,
or graphics to describe an object, a situation, or an event. A scientist is obliged to make the
information available to the community for independent confirmation and testing. Scientists
disseminate the results of their studies in journals, scientific meetings, seminars, and informal
networks. This dissemination contributes to the common core of knowledge of the past and
provides the vehicle for continuous review of this body of knowledge and for advancements in
science.

7. Hypothesizing
Hypothesizing is stating the proposed solutions or expected outcomes for your investigations
or experiments. It is an intrinsic and creative mental process. A hypothesis shows the expected
relationship between two variables in an attempt to explain a cause-and-effect relationship. It
should be testable. It is tested to help explain observations that have been made. It is often stated
as an “if and then statement.” An example of a hypothesis is “If salt is added to water, then it will
boil faster.”

8. Defining Operationally
To define operationally is to describe objects in the context of a common experience. An
operational definition tells one what to do to or with an object and what to observe as a result
of the action. It is written in terms of how an object works or how it can be used. Examples of
operational definitions are given below:

Object Operational Definition
A ruler is a tool that measures the length of an
object.


A bicycle is a two-wheeled mode of
transportation.

A bicycle can move a person from one place to
another.

A pen is a tool for writing.

9. Controlling Variables
A variable is a changeable factor that can affect an experiment. Controlling variables involves
deciding which variables or factors will influence the outcome of an experiment, situation, or
event, and deliberately controlling them systematically. Note how important it is to change only
the variable being tested and keep the other variables constant. If you allow more than one
variable to be changed, you cannot determine the cause of the changes you observe in the
independent variable. The variable you plan to experiment with is the manipulated or independent
variable, while the one being measured to determine its response is the responding or dependent
variable. The variables that you control or made the same in your experiment are the constant
variables.

(a) control (b) experimental

Fig. 1.6 The effect of salt on the boiling temperature of water

Many experiments have a control variable, which is a treatment that you can compare
with the results of your test groups. In the experiment on the temperature of hot water upon
the addition of salt, everything should be the same except the presence of salt. The beaker, the
amount of water, and other materials should be the same. The setup in which salt is not added
(setup A) is the control. The setup in which two tablespoons of salt is added (setup B) is the
experimental or test group. In this experiment, salt is the independent variable, temperature is
the dependent variable, and all the rest of the materials are the constant variables. The use of
experimental and control setups are only two ways of controlling variables.


10. Designing Experiments
Designing an experiment includes identifying materials and describing appropriate steps in
a procedure to test a hypothesis. A procedure is the plan that you follow in your experiment. It
includes the materials needed and how to use them.

11. Experimenting
Experimenting is carrying out an experiment by carefully following the steps in the procedure
so that the results can be verified by repeating the procedure several times.

12. Acquiring and Organizing Data
Acquiring data is the process of collecting qualitative and quantitative observations. Data can
be organized in several ways such as using tables and graphs.

13. Interpreting Data
Interpreting data involves analyzing, synthesizing, and evaluating trends or patterns in a
set of data. These patterns may be used to formulate hypotheses, make predictions, and draw
generalizations. Interpretation requires creative thinking that can result in a whole idea that
encompasses the data.

14. Identifying Cause-and-effect Relationship
Identifying causes and effects requires analytical thought as one seeks to distinguish cause
from effect. The cause always happens before the effect. The effect is a result. You identify
cause-and-effect relationships every day when you solve problems and make decisions. Learning
to identify cause-and-effect relationships can help you understand what has happened.

15. Formulating Models
Formulating models includes describing or constructing physical, verbal, mental, or
mathematical explanations of systems and interconnected phenomena that cannot be directly
observed. A model is used to simplify processes or structures.

The Chemistry Laboratory
Chemists need a place to conduct experiments and researches, and the laboratory is the ideal
venue. Many chemical products have been synthesized and various chemicals have been discovered
in laboratories. For a chemistry student, a laboratory is where you will apply the different chemical
principles that you will learn.

Safety in the Laboratory
Actual participation in the laboratory work is essential in the study of chemistry. Ideally, a
chemistry laboratory should have the following: (a) ventilation system, (b) sink, (c) work table,
(d) gas and water outlets, (e) trash bin, (f) fire extinguisher, (g) first aid box, (h) board for writing,
(i) cabinets for storage, and (j) fume hood. However, a laboratory may not have all of these things.
If that is the case, then certain experiments cannot be carried out in the laboratory.


Some things in the laboratory are
there not only for learning but also to Info Overload
maintain safety. Safety always comes
first. In the chemistry laboratory, you Fire is the most common serious hazard in a typical
will be working with an equipment or chemistry laboratory. While proper procedure and
a material that may cause accidents if training can minimize the chances of an accidental fire,
not handled properly. Accidents do you must still be prepared to deal with a fire emergency.
happen; that is why every precaution The different classes of fire are as follows:
must be taken to prevent them. Follow • Class A – ordinary combustibles (wood, paper,
the basic safety rules while working in plastics)
the laboratory. • Class B – flammable and combustible liquids
• Class C – flammable gases
1. Always follow your teacher’s
• Class D – combustible metals
instructions. Listen intently
• Class E – electrically energized equipment
and make sure that you
• Class F – cooking oils and fats
understand everything that
you have to do. Prepare Fire extinguishers are color coded so that you
everything you need. can identify them quickly and use the right type of
2. Take only the materials that extinguisher for a certain class of fire. The two most
you are asked to bring to common types of extinguishers in the chemistry
the laboratory. Remember laboratory are pressurized dry chemical and carbon
that food and drinks are not dioxide extinguishers. Dry chemical extinguishers are
allowed inside the laboratory. useful for class ABC fires, and hence, a better choice
for the chemistry laboratory. They leave a blanket of
3. Avoid playing inside the
nonflammable material on the extinguished material,
laboratory.
which reduces the likelihood of reigniting. Carbon
4. Handle chemicals with
dioxide extinguishers, on the other hand, are most
caution. Dispose of chemical
effective on class B and C fires. They do not work
wastes and other wastes
very well on class A fires because the material usually
properly.
reignites. They do not leave harmful residue. Since the
5. Use all laboratory tools gas disperses quickly, carbon dioxide extinguishers
properly. Handle them with are only effective from 3 to 8 feet. A carbon dioxide
care to avoid breakage. Check extinguisher is a good choice for an electrical fire
their conditions before you involving a computer or other delicate instrument. It is
use them. not suitable for outdoor use.
6. Do not deviate from the An easy acronym on using fire extinguishers is PASS:
experimental procedures.
Pull the pin that keeps the handle from being accidentally
7. Wear protective clothing such pressed. The pin is located at the top of the extinguisher.
as a laboratory gown, and use
protective gadgets such as Aim the nozzle toward the base of the fire. Remember to
goggles, masks, and gloves, stand approximately 8 feet away from the fire.
if necessary. If you have long Squeeze the handle to discharge the extinguisher. Once
hair, tie it back or wear a you release the handle, the discharge will stop.
hairnet.
Sweep the nozzle back and forth at the base of the fire.
8. Report any injury or any
After the fire appears to be out, watch carefully for
untoward incident to your
possibility of reignition.
teacher who is always there to


help you. Do not hesitate to ask your teacher if you have any question.
9. Return all chemicals and laboratory tools to the stock room or storage area. Do not take
home any chemical or laboratory tool.
10. Refrain from using cell phones and other electronic gadgets in the laboratory. Remove all
pieces of jewelry while working in the laboratory.
11. Wash your hands after handling chemicals. Clean also the laboratory materials that you have
used.
12. Do not play with chemicals and fire. Never taste any substance in the laboratory unless you
are told to do so.
13. Learn how to put out fire. Your teacher will demonstrate how to use the fire extinguisher if
the laboratory has one.
14. If acid is spilled on your skin, wash it with running water and sodium carbonate. Wash it
again with water afterward.
15. If a base is spilled on your skin, wash it with water and then with 1% acetic acid solution.
Wash again with water afterward.

Safety Symbols
Safety symbols are used in the laboratory to emphasize specific types of precautions. They
are used as aids to communicate information on hazards and the need for personal protective
paraphernalia, and give guidance and instruction in case of emergency. Remember to take the
necessary precaution when you see safety symbols.

Safety Clothing Eye Safety
It reminds you to wear It appears when a
your laboratory gown danger to the eye
properly. A laboratory exists. You should
gown protects your wear safety goggles
skin and your clothes when you see this
from any kind of spills. symbol.

Chemical Safety Fire Safety
It reminds you that the It reminds you that the
chemicals you use are chemical you use is
corrosive. Corrosive flammable. This also
materials are usually reminds you that care
strong acids or bases. should be taken around
They can cause burns open flames.
on your skin.

Thermal Safety Explosion Safety
It reminds you to use It reminds you that the
caution when handling misuse of chemicals
hot objects. can cause an explosion.


Disposal Alert Recycling Alert
It tells you that you It reminds you that the
can discard the materials can be stored
chemicals down the and recycled.
drain.

Electrical Safety Hygiene Safety
It reminds you that It reminds you to wash
care should be taken your hands thoroughly.
when using electrical
equipment.

Poison Safety Dispose Alerts
It indicates the It reminds you to throw
presence of a toxic or use chemicals and
poisonous material. materials in the proper
disposal area.

Laboratory Tools
Chemistry involves laboratory investigations. You must know the basic apparatus used in
chemistry to ensure that your investigations proceed smoothly. The following are the common tools
that you will use in the laboratory:

Alcohol burner – is Stirring rod – is used for
a source of heat. stirring substances and
transferring liquids to
another container.

Beaker – is used to Pipette bulb or aspirator
contain liquids. – is used to clean the
pans of platform balance
and get liquid using a
pipette.

Bunsen burner – is Platform balance – is
a source of heat. used to measure the mass
of a substance.


Burette – is used Reagent bottle – is a
to measure volume storage vessel of
of solutions during chemicals.
titration.

Ceramic square – Rubber stopper –
supports hot supports thermometer
apparatus to and covers the openings
prevent breakage. of narrow-mouthed
containers.

Clay triangle – Rubber tubing – connects
supports a crucible. a Bunsen burner to a gas
outlet.

Crucible tongs – is Test tube brush – is used
used to hold a to clean the test tubes.
crucible and its
cover.

Double burette Erlenmeyer flask – is
clamp – supports used to contain liquids.
burette during
titration.

Test tube clamp or Test tube holder – is used
utility clamp – to hold a test tube.
supports the test
tube and burette.


Evaporating Test tube rack – supports
dish – is used to test tubes.
evaporate liquids.

Flame loop – is Thermometer – is used to
used to hold measure temperature.
chemicals during
flame test.

Florence flask – is Triple beam balance –
used to boil is used to measure mass
liquid solutions. of a substance.

Forceps – is used Tripod – supports the
to get small clay triangle or wire
objects. gauze.

Funnel – is used to Volumetric flask – is used
transfer liquids to to measure volume of
another container liquids.
and support filter
paper during
filtration.
Graduated cylinder Wash bottle – is used to
– is used to wash the inner sides of
measure volume of the apparatus.
liquids.

Iron ring – Watch glass – is a
supports the wire container used to observe
gauze or clay small specimens.
triangle.


Iron stand – Wire gauze – regulates
supports the iron heat of the flame.
ring or clamp.

Dropper pipette Spot plate – is a reaction
or dropper – is vessel used for small
used to transfer amounts of substances,
small amounts of especially when using
liquids to another litmus paper.
container.
Mortar and Spatula – is used for
pestle – is used getting solid chemicals
for pounding or from reagent bottles.
grinding solid
chemicals to
powder form.
Crucible and cover Fish tail – is used for
– is a vessel used spreading the flame of
in heating small Bunsen burner.
amounts of solid
substances at high
temperature.
Bell jar – is used Glass tubing delivery
to cover and store tubes – is used to make
volatile chemicals. droppers for capillary
tubes.

Desiccator – is Syringe – is used for
used for removing sucking and expelling
the moisture from liquid in fine stream.
specimens.

Measuring pipette Transfer pipette – is used
– measures exact to transfer liquids.
volume of liquids.


CSI

Design and make your own laboratory apparatus. Demonstrate its use in class. Then fill out
the following information:

Name of laboratory apparatus:
Use:
Materials and cost:
How it looks like:
How it works:

Laboratory Techniques
Conducting an experiment is the best way to learn chemistry. Poor results in a chemistry
experiment are often the result of poor laboratory techniques. A laboratory technique is not random,
but a rational approach to a problem. The most common errors in a chemistry experiment are
chemical contamination, the loss of precipitates, spilled liquids, and the like. To avoid these errors,
you must practice good basic laboratory techniques.

Using Chemicals
Chemicals are stored in reagent bottles. Always read the label on a reagent bottle before using its
contents. Remove the lid and place it on top of the table upside down. Get only the desired amount
of the chemical you need. Never touch a chemical with your hands. Use a spatula for solids and a
dropper for liquids.

1. Solids
To obtain a solid, remove the lid or stopper and place it upside down on
the table. Rotate and tilt the bottle at the same time to dispense the solid
slowly to a clean dry beaker.
You can also use a clean dry spatula to
spoon out a small amount of the solid
chemical.

If the container has a narrow mouth like that of a test tube, use
a folded or rolled paper, then gently tap the paper to transfer its
content into the test tube.

2. Liquids
To obtain a liquid from a reagent bottle, grasp the vertical flange between your third and
fourth fingers, palms up. Holding the flange this way, bring the neck of the bottle in contact with


the rim of the receiving container. Pour the liquid down the side to
avoid spattering and spilling. Replace the flange when finished.
Note: The flange must never touch the laboratory countertop or the
side of the receiving container to avoid contamination.

To transfer a liquid using
a pipette, use an aspirator
to avoid contamination.
Place an aspirator on top
of the pipette as illustrated. Compress the aspirator.
Slowly release pressure so that the liquid is drawn into
the pipette. Remove the aspirator and simultaneously
place your index finger over the end of the pipette.
Insert the tip of the pipette into the receiving container.
Hold it vertically and allow pipette to drain freely.

Liquids can also be
transferred with the use of a
stirring rod. Pour liquids into
another container using a glass
rod in an upright position of
the receiving container.

In obtaining liquids
from bottles equipped with
medicine dropper, be sure that it never touches both the
container and the contents of the receiving vessel.

Measuring Liquids
The graduated cylinder and pipette are two commonly used
devices for measuring liquid volumes. Study carefully the
particular device to determine how it is calibrated and how to
use it to measure liquids accurately. When reading the level of
liquid in any liquid measuring device, read the bottom of the
meniscus (lowest portion of the convex dip of the liquid as it
sits in the graduated cylinder), with your eye at the same level
as the liquid surface.

Using the Laboratory Thermometer
Never shake a laboratory thermometer. Immerse the bulb of the thermometer in the substance
whose temperature you are measuring. Allow the alcohol level to stabilize and read the thermometer.
Be sure to study the calibrations on the thermometer to determine how it can be read accurately.Do
not use a thermometer as a stirring rod for solutions. Remember that the bulb of the thermometer is
delicate. If a thermometer breaks, immediately inform your teacher.


Using a Bunsen Burner
The Bunsen burner is used frequently in the laboratory as a source of
heat. It is designed so that gaseous fuel may be mixed with the correct
barrel
amount of air to yield the maximum amount of heat. It can produce three
different types of flames: safety flame, blue flame, and roaring blue flame.
1. Safety flame – It is yellow or orange in color. It is the coolest flame, air hole
approximately 300°C. It is the flame produced when air holes are
gas inlet
closed. It is used only to show that the Bunsen burner is on and not
for heating.
2. Blue flame – It is also called medium flame, nonluminous flame,
or invisible flame. It is approximately 500°C. It is the most
commonly used flame.
3. Roaring blue flame – It is the hottest flame, approximately 700°C.
It is characterized by a light blue triangle in the middle. It is so- base
named because it makes a roaring sound.
The correct steps in setting up and operating the Bunsen burner safely and appropriately are as
follows:
1. Connect the Bunsen burner to the gas supply using a rubber tubing.
2. Completely close the air holes.
3. Turn the gas valve on the gas outlet to the fully open position.
4. Light the burner by holding a match to the side of the mouth of the burner. If you stick the
match in the middle of the gas stream, the flame is usually blown out before the burner lights.
5. Open the air holes slowly to admit more air into the flame and produce a light blue flame.
Adjust the air holes and gas supply to produce the desired size of flame.
6. Turn the burner off at the main gas supply valve when done.

Heating Solids and Liquids
1. Solids
To heat solids in a test tube, clamp the tube to an iron stand at
45°. The flame is passed slowly back and forth along the bottom
of the tube.
Solids may be heated to high temperatures in a crucible
supported by a clay triangle over an iron ring or tripod. The
crucible is carefully placed on a clay triangle either at upright
position or at a certain angle.

2. Liquids
When heating liquids in a beaker, place it over a wire gauze
supported by an iron ring attached to an iron stand. The wire gauze
distributes the heat evenly and prevents cracking of the container due
to sudden temperature changes. During heating, stir the liquid while
carefully heating to avoid lumping. Uneven boiling can cause the
dangerous spattering of large quantities of hot liquid.


When heating liquids in a test tube, hold the tube with a test tube
holder at 45° and pass it back and forth over the flame of a burner. The
test tube should be heated just below the liquid level, but never at the
bottom of the tube. (Note: Heat the tube with the open end pointed
away from you and from anyone else. Never heat the tube directly at
the bottom, the contents may be ejected suddenly due to superheating.
Never boil a liquid in a tube, which is more than a quarter full.)

Measuring Mass
The balance is an instrument used
for determining the mass of a substance. pan
Among the various types of laboratory riders
balances, the most commonly used is the
triple beam balance, although top-loading
digital balances are becoming popular.
In carrying the balance, place one
hand under the base and the other hand on
the arm. Be sure that all riders are back
to the zero point. beams
adjustment
To measure the mass of a substance, screw base arm
the pointer must be at the zero scale. Put
all riders at the zero point. If the pointer
is not in exact balance, use the adjustment
screw to point it back to the zero mark. Never put chemicals directly on the balance pan. Use a paper
box or a clean and dry empty container. Get the mass of the paper box or container before adding
the chemicals. Once you have placed the object to be weighed on the pan, move the riders along the
beams beginning with the largest mass first. Make sure all riders are in a notch before you take a
reading. Return all the riders to zero point after weighing. Always keep the balance clean.

CSI
Creating a Paper Box

1. Fold the paper in half, then extend it back out.
Fold each half inward again to end up in the
middle line. (1)

2. Turn the paper sideways and repeat step 1.
However, after the second fold, fold back out
again and straighten the
paper.
3. Fold the four corners inward, but do
(2)
not exceed the lines from the second (3)
fold in step 2. Make sure not to fold
in more than a third of the width.


4. Fold the edges on the middle line out over the triangles
made in step 3 in a straight line.
5. Pull out slowly both sides over the middle line, (4)
strengthening the edges and corners as you proceed.
Make sure that the corners are strong and forming 90°.

(5)

Using the Platform Balance
Objectives:
1. Manipulate the platform balance correctly.
2. Compare the mass of a cup of sand with a cup of salt.
Materials:
platform balance, salt, sand, measuring cup, set of weights
Procedure:
1. Use the paper box you made. Place it on the left pan of the platform balance. Determine the
mass of the paper box by moving the riders until the pointer reaches the point. Record the
mass in the data table.
2. Put 1 cup of sand in the paper box. Bring the pointer to the zero mark. Record the mass in
the data table.
3. Make another paper box and determine its mass. Record the mass in the data table.
4. Put 1 cup of salt in the paper box and determine its mass. Record the mass in the data table.
Data Table
Sand Salt
Mass of paper box
Mass of paper box + sample
Mass of sample

Questions:
1. Why should you determine the rest point of a platform balance before getting the mass of a
sample?
2. What are the possible causes of error in weighing?
3. Which is heavier: a cup of salt or a cup of sand? Why?


Chapter Test

Choose the letter of the correct answer.
For numbers 1–3, refer to the choices below:
a. beaker
b. crucible and cover
c. graduated cylinder
d. test tube
1. It is a deep, wide-mouthed, thin-walled, and cylindrical device with a spout.
2. It is a container made of porcelain and is used for heating substances that requires extreme heat.
3. It is a glass tube closed at one end and is used in testing chemicals.
For numbers 4–5, refer to the choices below:
a. black magic
b. alchemy
c. traditional chemistry
d. modern chemistry
4. During this period, people believed that lead can be transmuted into gold.
5. During this period, people believed in the four elements: fire, earth, water, and air.
6. Which of the following is not a qualitative observation?
a. The red rose is wilting slowly.
b. The stem of the rose has many thorns.
c. The stem of the rose is 25 centimeters long.
d. The rose has a sweet scent that fills the room.
7. Which of the following is not an integration of chemistry and information technology?
a. Database for all chemicals found in the world
b. Increased sales among all kinds of consumers
c. Higher resistance of computers to heat and force
d. Cheaper raw materials that can be used for making microchips
8. Which of the following is not correct?
a. biochemistry: living organism
b. inorganic chemistry: carbon containing compounds
c. physical chemistry: properties of matter
d. polymer chemistry: plastics
9. Which of the following is not a contribution of Antoine Laurent Lavoisier?
a. disproof of the phlogiston theory
b. metric system
c. The Skeptical Chemist
d. law of conservation of mass


10. Who discovered Prialt, a pain reliever derived from cone snails?
a. Amando Kapauan c. Baldomero Olivera
b. Anacleto del Rosario d. Julian Banzon
For numbers 11–12, refer to the hypothesis below:
If cologne is not covered, it will evaporate.
11. Which set of materials can be used to test the hypothesis?
a. Container A is filled with cologne and is covered; container B is empty and uncovered.
b. Containers A and B are each filled with the same amount of or equal volume of cologne; one
is covered and the other ne is uncovered.
o
c. Containers A and B are filled with cologne; both are covered.
d. Containers A and B are filled with cologne; both are uncovered.
12. What is the dependent variable?
a. beakers
b. brand of cologne
c. exposure to air
d. volume of cologne
13. What is the first thing that you will do when an acid is spilled on your hand?
a. Go to the hospital.
b. Inform your parent about the accident.
c. Wash your hand with plenty of water.
d. Apply burnt ointment and cover it with gauze.
14. When carrying out experiments in the laboratory, which of the following should not be done?
a. making observations
b. tasting chemicals
c. taking measurements
d. recording data
15. When you lit the Bunsen burner, a beaker with alcohol suddenly catches fire. What will you do?
a. Turn on the fire alarm.
b. Quickly turn off the Bunsen burner. Then, smother the beaker with damp towel.
c. Call the fire department.
d. Call the police.


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