Chemistry edexcel as unit 1 chapter 1 chemical quantities_v0.03

AS
Unit 1 Chapter 1 - Chemical Quantities
1. Elements, Compounds and Bonding
2. Types of Chemical Change:
Thermal Decomposition
Acids, bases and alkalis, neutralisation
Precipitation reactions
Redox reactions
6 & 7 . Reacting quantities: molar mass
and The Avogadro constant
8. Empirical and molecular formulae
9. Linking reacting quantities to
chemical equations
10. Reacting quantities: volumes of gase
11. How much hydrogen is produced
when
lithium reacts with water?
12. Describing concentrations in
gases
and solutions
13. The percentage yield of a chemical
reaction
14. Calculating the percentage
yield from
the preparation of a salt
15. The importance of atom economy

AS
Unit 1
Elements, Compounds and
Bonding
Textbook chapters: 1.2 and 1.3

AS
Key questions…
• How do chemists describe
chemical substances?
• How to chemists show the
changes in chemical
reactions?

AS
What to do…
• Use you GCSE knowledge to
create a mind-map by
matching and grouping the
sort cards
• Some of these came from
actual exam MCQ questions
• NOTE: Some statements are NOT

AS
What to do…
• Use the
molecular
models to
build:
• methane
• Water
• oxygen
• carbon
dioxide
QUESTIONS
1.Why does the…
a) hydrogen have
1 hole?
b) oxygen have 2
holes?
1.What do the
connectors
represent?

AS
How to chemists show the
changes in chemical reactions?
Reactants Products
methane oxygen carbon dioxide+ + water
O
O
O
O HO
H
O
O
H O
H
HC
H
O
C
HO
H
+ +

AS
Watch the reaction between
hydrogen and oxygen
REACTION: hydrogen & air
Word Equation:
Particles:
Chemical Equation:
hydrogen + oxygen  water
O
O
+
HO
H
H
H
H
H
HO
H
How many
oxygen atoms
are there on the
reactant side?
How many oxygen
atoms are there
on the product
side?
How many
hydrogen atoms
are there on the
reactant side?
So, double the
number of water
molecules
How many
hydrogen atoms
are there on the
product side?
So, double the
number of
hydrogen molecules
You cannot
change the
formula of
a molecule
Each hydrogen
molecule contains 2
hydrogen atoms
2 12 4
H2 + O2  H2O2 2
To show that there are 2
molecule, you put the ‘2’
IN FRONT of the
chemical formula
(g) (g) (g)
What about the states:
• (s) - Solid
• (l) - Liquid
• (g) - Gas
• (aq) – dissolved (aqueous)
+

K + Cl2 
2KCl
Balanced or unbalanced?

CaCO3  CaO +
CO2

Na + H2O  NaOH + H2

2Li + I2  2LiI

2K + 2H2O  2KOH + H2

NaOH + HCl  NaCl + H2O

2Rb + 2Br2 
2RbBr

CH4 + O2  CO2 + 2H2O

2Fe + 3Cl2  2FeCl3

2NO + CO  N2 + 2CO2

AS
Plenary and Homework
• List 2 chemistry facts you had
(nearly) forgotten over the summer
Homework
• Create a mind map covering ideas
about chemical bonding and
structures
• If you can, take a photo and upload
it to Edmodo

AS
Unit 1
Types of Chemical
Change:
Thermal Decomposition
Textbook chapter: 1.4

AS
Starter
• List all the different types of
chemical reaction you can think
of…In this unit we will look at:
• Thermal decomposition
• Reactions of acids
• Reactions of bases and alkalis
• Neutralisation
• Precipitation

AS
Objectives
• Explain how we classify
different types of chemical
reaction?
• Describe and interpret
decomposition reactions:
• Write balanced equations
• Explain the processes

AS
What to do…
• Watch the demonstration of
the thermal decomposition of
Ammonium dichromate

AS
What to do…
• Copy and balance the
equation:
(NH4)2Cr2O7(s)  Cr2O3(s) + N2(g)
+ H2O(g)
• What do the brackets around (NH4)
mean?
• If ammonium has a charge of +1,
what is the charge on the
4

AS
Read page 9 in
your textbook
and make
notes on…
Notes
• Definition of
thermal
decomposition
• Equation for
decomposition of
CaCO3
• Uses of limestone,
quick lime, slake
lime

AS
What to do…
• Carry out the thermal
decomposition of hydrated
copper sulfate
• What type of bonding does
copper sulfate have?
• How can you explain the
structure of the hydrated form?

AS
• Is burning methane ‘thermal
decomposition’?
• What other types of
decomposition might occur?
• Why do compounds decompose?
Homework
• Research other thermal
decomposition reactions - add
examples to

AS
Unit 1
Types of chemical
change:
Reactions of acids, bases
and alkalis, neutralisation

AS
Starter
• You have got 90 seconds to
list everything you know
about acids...
0
15
45
3060
75

AS
Objectives
Must
• Explain what acids are
• Explain what bases and alkalis are
• Write balanced (full and ionic)
equations describing the reactions of
acids
Should
• Explain neutralisation reactions using
ionic theory

-
--2
-
Acids
O
O
O
O
S
H
H
Cl H H
H
C
H
H
H
C
O
O
H+
H+
H+
H+
H+
ON
O
O

AS
Ionic equations
• Write down the definition of an acid
HCl(g) Cl-(aq)H+(aq) +water
This is an ionic equation
• Write down the ions formed when
hydrogen chloride reacts with water to
produce hydrochloric acid
• Write down the definition of an ionic
equation

AS
Acid equations
• Complete the ionic equations for the
other acids on the worksheet
• Complete the equations for the 4 key
reactions of acids

AS
SALT + hydrogen
MgCl (aq) + H2(g)
Mg(s)+ 2H+(aq) + 2Cl-(aq) Mg(aq) + H2(g) + 2Cl-(aq)
Mg(s) + 2H+(aq) + 2Cl-(aq) Mg(aq) + H2(g) + 2Cl-(aq)

2++++
LiNaKCa
-
O HO HO HO H
O H
O H
-
O H
-
O H
-
O H
-
O H
Alkalis

HCl(aq) + NaOH(aq)  NaCl(aq) + H2O(l)
H+
H+ H+
H+
H+
H+
H+
H+
H+
H
O-
H
O-
H
O-
H
O-
H
H
O
H
O-
H+
H+
H+
H+
H+
H+
H
O-
H
O
H
H
O-
Neutralisation
Na+
Cl- Na+
Na+
Na+s
Cl-
Cl-
Cl-
Cl-
Cl-
Cl-
Cl-
Na+
H+
(aq) + OH-
(aq)  H2O(l)

AS
Bases
• Bases are the opposite of acids. If
acids give up (donate) hydrogen ions,
then bases…?
• Write down the definition of a Base
• Alkalis are Bases that dissolve in water.
They include:
• the hydroxides of sodium and
potassium
• the carbonates of sodium and
potassium

AS
Bases
LiOH(s) OH-(aq)lI+(aq) +water
• Write down the ionic equation showing
what happens when lithium hydroxide
dissolves in water

AS
Bases
• Write down the ionic equation for
ammonia reacting with water to form an
alkali (containing OH- ions)
NH3(g) OH-(aq)NH4
+(aq) +H2O(l)+

AS
Bases
Acids, Bases and Alkalis
• Draw a diagram explaining relationship
between Acids, Bases and Alkalis
Acids Alkalis

AS
Unit 1
Types of chemical
change:
Precipitation

AS
Starter
• Explain what an ionic equation
is
• Explain what a spectator ion is
• Explain how you work out the
charges on simple ions (e.g.
sodium, chloride)

AS
Objectives
Must
• Recall the test for metal ions using
sodium hydroxide
Should
• Write balanced (full and ionic)
equations describing precipitation
reactions

AS
What to do…
• Complete Experiment 1.3k –
Ionic equations for simple
reactions

AS
FULL CaCO3(s) + 2HCl(aq)  CaCl2(aq) + H2O(l) + CO2(g)
IONI
C
CaCO3(s) + 2H+(aq)  Ca2+(aq) + H2O(l) + CO2(g)
1. Calcium carbonate and dilute hydrochloric
acid
ACID + CARBONATE  SALT + WATER + CARBON
DIOXIDE
Effervescence is easy to see here as the colourless gas,
carbon dioxide, is produced. The solid carbonate is
dissolving, but the reaction is too slow to see this
happening.
Experiment 1.3k – Ionic equations for simple reactions

AS
FULL
CuCO3(s) + H2SO4(aq)  CuSO4(aq) + H2O(l) +
CO2(g)
IONI
C
CuCO3(s) + 2H+(aq)  Cu2+(aq) + H2O(l) + CO2(g)
2. Copper(II) carbonate and dilute sulfuric acid
ACID + CARBONATE  SALT + WATER + CARBON
DIOXIDE
Again we see effervescence caused by the release of carbon
dioxide gas. This time the solid green copper(II) carbonate is
seen dissolving although some still remains at the end. The
appearance of a blue solution of copper(II) ions is also observed.

AS
FULL Zn(s) + 2HCl(aq)  ZnCl2(aq) + H2(g)
IONI
C
Zn(s) + 2H+(aq) ®Zn2+(aq) + H2(g)
3. Zinc metal and dilute hydrochloric acid
ACID + METAL  SALT + HYDROGEN
Effervescence is caused this time by the release of hydrogen gas.
The metal is dissolving, but the reaction is too slow to see this
happening.

AS
FULL NiO(s) + 2HNO3(aq)  Ni(NO3)2(aq) + H2O(l)
IONI
C
NiO(s) + 2H+(aq)  Ni2+(aq) + H2O(l)
4. Nickel(II) oxide and dilute nitric acid
ACID + BASE  SALT + WATER
The black nickel(II) oxide solid is seen dissolving and producing a
green solution of nickel(II) ions.

AS
FULL
2AgNO3(aq) + K2CrO4(aq)  Ag2CrO4(s) +
2KNO3(aq)
IONI
C
2Ag+(aq) + CrO4
2-(aq)  Ag2CrO4(s)
5. Silver nitrate and potassium chromate
solutions
This is a precipitation reaction. Insoluble, orange-red silver
chromate solid is produced.

AS
FULL BaCl2(aq) + H2SO4(aq)  BaSO4(s) + 2HCl(aq)
IONI
C
Ba2+(aq) + SO4
2-(aq)  BaSO4(s)
6. Barium chloride and dilute sulfuric acid
This is another precipitation equation. Dilute sulfuric acid is
ionised in aqueous solution and produces a white precipitate of
barium sulfate.

AS
FULL Zn(s) + CuSO4(aq)  ZnSO4(aq) + Cu(s)
IONI
C
Zn(s) + Cu2+(aq)  Zn2+(aq) + Cu(s)
7. Zinc metal and copper(II) sulfate solution
This is a displacement reaction. Zinc is more reactive than copper
so displaces it from its salt. We can see the appearance of brown
copper metal on the surface of the zinc and the loss of the blue
copper(II) colour as it is replaced by the colourless zinc ion.

AS
FULL Cu(s) + 2AgNO3(aq)  Cu(NO3)2(aq) + 2Ag(s)
IONI
C
Cu(s) + 2Ag+(aq)  Cu2+(aq) + 2Ag(s)
8. Copper metal and silver nitrate solution
This is another displacement reaction. Copper is more reactive
than silver so displaces it from its salt. We can see the
appearance of grey silver metal on the surface of the copper and
the appearance of the blue copper(II) colour.

AS
• Explain what happens in
displacement reactions
Homework
• Read ‘Precipitation’ on pages
12-13 and make notes
• Complete the Activity on
page 12-13

AS
Unit 1
Types of chemical
change:
Redox

AS
Objectives
Must
• Appreciate how chemists
determine the composition of
substances
Should
• Describe redox reactions for ions
with different oxidation numbers

AS
What to do…
• Complete Experiment 1.3i –
The reaction of iron with
copper(II) sulfate

AS
Experiment 1.3i – The reaction of iron with copper(II)
• From the reactivity series we know that iron is
more reactive than copper, and so should displace
the copper from its compounds.
• However, iron forms two series of compounds -
one containing the iron(II) ion and one containing
the iron(III) ion.
• In this experiment we will carry out a gravimetric
analysis in order to deduce which iron compound is
formed in this reaction. The two possible
equations are:
1. Fe(s) + Cu2+(aq) ®Fe2+(aq) + Cu(s)
2. 2Fe(s) + 3Cu2+(aq)  2Fe3+(aq) + 3Cu(s)

AS
• We shall weigh out exactly 0.01 moles of iron
powder (0.56 g) and react it with excess
copper(II) sulfate solution.
• If equation 1 is correct we would expect to
obtain 0.01 moles of copper (a 1:1 ratio)
• If equation 2 is correct we would expect to
obtain 0.015 moles of copper (a 2:3 ratio).
Experiment 1.3i – The reaction of iron with copper(II)

AS
Unit 1
Reacting Quantities:
Molar Mass
Textbook chapters: 1.5

AS
Starter
• Why do chemist need to
measure the amounts of
substances?
• How can chemists physically
measure how much ‘stuff’
they have got?

AS
Objectives
Must
• Understand the terms:
• relative atomic mass
• relative formula mass
• Mole
• molar mass
• Percentage composition (mass)
• Avogadro’s Constant
Should
• Calculate the number of particles (atoms,
ions or molecules) in a known mass of
substance using its molar mass and the

What to do…
• Watch the demonstration
(Mg+CuO)
• What are the challenges with
taking measurements in
chemistry?
(golf / tt ball demo)

Relative Atomic Mass
• In water, oxygen makes up
90% of the mass but
accounts for only 1/3 of the
number of atoms
H
H
H
H
• How do Chemists make the link between mass and
number of atoms? relative atomic mass (Ar)
• What is ‘relative atomic mass’?
(Record this on your ‘Key Terms’ worksheet)
Mass of an atom relative to 1/12th of the carbon-12-
isotope (12C) – which is assigned an Ar of 12
• Why carbon-12? Abundant, solid
Key Terms
Worksheet

Relative Atomic Mass
• What are the units of Ar?No units – it is ‘relative’
• How can you find the Ar of an element?
Periodic Table of the Elements
CHEMICAL SYMBOL
PROTON NUMBER = number of
protons (obviously)
RELATIVE ATOMIC MASS, Ar
(“Mass number”) = number of
protons + number of neutrons

The Chemist’s Pet
• What can we say about 14g Nitrogen, 1g
Hydrogen, 56g Iron?
• What do each of these amounts of substance
equal to?
They have the same number of atoms
A ‘mole’ =
Molar Mass = The relative atomic mass in grams
Unit = g/mol or g mol-1
The amount of
substance which
contains as many atoms
as there are atoms in
12g 12C

Calculating Moles
Calculating the number of moles:
Number of moles = mass (grams)
molar mass ( g mol -1)
6.Calculate the number of moles in:
a. 4g of oxygen
b.2g hydrogen
c. 8g of nitrogen
4 / 16 = 0.25 mol
2 / 1 = 2 mol
8 / 14 = 0.57 mol

Relative Formula Mass
• Moles can also be used to measure the amounts of
compounds present
• Methane is made when:
• 1 C reacts with 4 H atoms, or when
• 1 mole of C reacts with 4 moles of H
• The Formula Mass (Mr) can be calculated by
________ together the ________ _______
________ of the individual atoms that make up
that compound
relativeatomic masses
adding

Calculating Relative Formula Mass
7. Calculate the formula mass (Mr) of the following
compounds:
1) HCl
2) NaOH
3) MgCl2
4) H2SO4
H=1, Cl=35.5 so Mr = 36.5
Na=23, O=16, H=1 so Mr = 40
Mg=24, Cl=35.5 so Mr = 24+(2x35.5) = 95
H=1, S=32, O=16 so Mr = (2x1)+32+(4x16) = 98

Dr Hill
Formula Units
• The basic unit of a substance
• single atoms
• molecules
• groups of ions
Substance Formula Unit Relative Formula Mass
copper
sodium
chloride
oxygen
Cu
NaCl
O2
64
(23 + 35.5) = 58.5
32

Calculating moles of formula units
Number of moles of formula units = mass (in gram
molar mass (g mol-1)

Calculate the percentage mass of
magnesium in magnesium oxide, MgO:
Ar for magnesium = 24 Ar for oxygen = 16
Mr for magnesium oxide = 24 + 16 = 40
Therefore percentage mass = 24/40 x 100% =
60%
Percentage mass (%) =
Mass of element (Ar)
Relative formula mass Mr
x 100%
Calculating Percentage Composition

Calculate the percentage mass of the following:
1) Hydrogen in hydrochloric acid, HCl
2) Potassium in potassium chloride, KCl
3) Calcium in calcium chloride, CaCl2
Mr for HCl = 1 + 35 = 36
% mass = 1 / 36 x 100 = 2.8%
Mr for KCl = 39 + 35 = 74
% mass = 39 / 74 x 100 = 52.7%
Mr for CaCl2 = 40 + (2x35) = 110
% mass = 40 / 110 x 100 = 36.4%

The Avogadro Constant
• The number of formula units in a mole
of a substance is constant
• Doesn’t matter what you are measuring
(atoms, molecules, electrons)
• The Avogadro constant =6.02 x 1023
602000000000000000000000

AS
Plenary
• 2 minutes to learn the terms
on the key terms sheet and
test your partner
Homework
• Answer question 18-22 on
page 17

AS
Unit 1
Empirical and molecular
formulae

AS
Starter
• Write down the formula of all of
the compounds below…
• sodium chloride
• barium sulphate
• Carbon dioxide
• helium
• ammonia
• oxygen

AS
Starter
• Test on key terms…
• Define the following
(precisely):
• relative atomic mass
• relative formula mass
• mole
• molar mass
• percentage composition

AS
Objectives
elements
• Calculate the empirical
formula of a compound from
measurements of the mass
• Calculate percentage masses
of the elements in a
compound

AS
What to do…
• Read ‘1.6 Finding formulae on
pages 17-18 and make notes
• Complete Activity on pages
18-19
• Answer questions 23-24 on
page 18

AS
Past Exam paper questions… June 2010

AS
Unit 1
Linking reacting
quantities to chemical
equations

AS
Starter
Recap of Ar and Mr
• What is the Ar of He?
• What is the Mr of Fe2O3?
• How many molecules are
there in 9ml of water?

AS
Objectives
• Calculate the masses of reactants
and products using the idea of
molar mass

AS
What to do…
• Listen to the teacher review
how chemists calculate the
masses from a chemical
equation
• Write down the 4 stages
used to calculate the masses

AS
Try these questions from page 2

AS
Unit 1
Reacting quantities:
volumes of gases

AS
Starter – units of measure
Temperature
• Use the following information to answer the
questions below:
• The (SI) standard unit of temperature is Kelvin (K)
• The Celsius (centigrade) scale (oC) is also commonly
used
• The Celsius and Kelvin (K) temperature have the same
size units
• -273oC = 0K
Questions
1. What is 0oC in Kelvin?
2. What is 10oC in Kelvin?
3. What is 298K in oC?
4. What is 10K in oC?

AS
Starter – units of measure
Volumes
• 1000 cm3 = 1 dm3
• To convert cm3 into dm3 you divide by
1000
Questions
• What is 150cm3 in dm3?
• What is 25cm3 in dm3?
• What is 1.5dm3 in cm3

AS
Objectives
• Calculate the volumes of gases
using chemical equations and the
concept of molar volume
• Deduce simple equations involving
gases using the concepts of molar
volume and moles (opposite to
above)

AS
Avogadro’s Law
In 1811 Avogadro developed a law…
Avogadro’s Law
Equal volumes of all gases at the same temperature and
pressure contain an equal number of molecules
Molar Volume: the volume occupied by 1 mole of any gas
• At r.t.p. (room temperature and pressure) = 24dm3
• At s.t.p. (standard temperature and pressure) = 22.4
dm3

AS
Calculations involving molar volumes
Volume of gas (cm3)=moles of gas x molar volume (cm3
mol-1)

AS
mol-1)
24dm3 at r.t.p.
22.4 dm3 at s.t.p.

AS
mol-1)
24dm3 at r.t.p.
22.4 dm3 at s.t.p.
…in cm3 these are?

AS
mol-1)
24dm3 at r.t.p.
22.4 dm3 at s.t.p.
24 000 cm3 at r.t.p.
24 000 cm3 at r.t.p.
…in cm3 these are?

AS
Past Exam paper questions…
June 2011

AS
Past Exam paper questions…
June 2010

AS
Plenary
Homework
• Write down the equation linking moles to
volumes of gases
• How much volume would ½ mole of He occupy?
• How much volume would 8g of O2 occupy?
• Answer questions 30-32 on page
22

AS
Unit 1
How much hydrogen is
produced when lithium
reacts with water?

AS
Objectives
• Deduce simple equations involving
gases using the concepts of molar
volume and moles (opposite to
above)

AS
What to do…
• Carry out Experiment 1.3i –
The reaction of lithium with
water

AS
Experiment 1.3i – The reaction of lithium with wat
• 0.050 g of lithium is 0.050 ÷ 6.94 =
0.0072 mol of Li
• Assuming molar gas volume at RTP =
24000 cm3 mol-1
• We collected 83 cm3 of hydrogen gas
83 ÷ 24000 = 0.0035 mol of H2
• This give a ratio Li : H2 of 0.0072/0.0035
: 1 or 2.06 : 1
• 2 Li to 1 H2

AS
Unit 1
Describing
concentrations in gases
and solutions

AS
Objectives
• Calculate the concentrations of solutions in
grams per cubic decimetre (g dm−3) and
moles per cubic decimetre (mol dm−3)
• Calculate the amount of substance (number
of moles) in a solution of known
concentration
• Calculate the concentrations of very dilute
solutions in:
• millimol dm−3
• parts per million (ppm) – for pollutants
in water and trace gases in the

AS
What to do…
• Listen to the explanation of
how to calculate
concentrations of solutions
and very dilute solutions

AS
Plenary
Homework
• Write the general formulae
used to calculate concentrations
in g dm-3 and mol dm-3
• Read ‘1.8 Theoretical and
percentage yield’ and ‘Atom
economy’ on pages 25-26 ready

AS
Unit 1
Theoretical and
Percentage Yield

AS
Starter
• Explain to your partner how
to calculate percentage
yield…you’ve got 90s

AS
Starter
• Explain to your partner how
to calculate atom
economy…you’ve got another
90s

AS
Objectives
• Use the actual and theoretical
yields in chemical processes to
calculate percentage yields

AS
What to do…
• Carry out Experiment 1.3j –
Making a salt and measuring
percentage yield

AS
Experiment 1.3j – Making a salt and measuring percentage
• Formula for Mohr's salt : FeSO4.(NH4)2SO4.6H2O
• Molar mass of 392 g mol-1.
• If we made 0.05 moles of this salt, the theoretical
yield would be 0.05 × 392 = 19.6 g
• Actual yield = 8.672 g
• percentage yield = 8.672 ÷ 19.6 × 100 = 44%
Why such a low yield?
• Much of the Mohr's salt was lost when we filtered off
the solution (which is saturated with Mohr's salt) from
the crystals which had formed.
• You should have noticed some unreacted iron showing
that this reaction was incomplete. This means that less
than 0.05 moles of iron(II) sulfate was produced so
lowering the percentage yield.
• There were also some transfer losses with some of the

AS
Homework
• Answer questions 36-37on
page 26

AS
Unit 1
The importance of
atom economy

AS
Objectives
• Use equations to calculate the atom
economies in chemical processes

AS
What to do…
• Answer question 38on page
27

Chemistry edexcel as unit 1 chapter 1 chemical quantities_v0.03

Empfohlen

Empfohlen

Weitere ähnliche Inhalte

Was ist angesagt?

Was ist angesagt? (20)

Andere mochten auch

Andere mochten auch (12)

Ähnlich wie Chemistry edexcel as unit 1 chapter 1 chemical quantities_v0.03

Ähnlich wie Chemistry edexcel as unit 1 chapter 1 chemical quantities_v0.03 (20)

Kürzlich hochgeladen

Kürzlich hochgeladen (20)

Chemistry edexcel as unit 1 chapter 1 chemical quantities_v0.03