The document contains four chemistry assignments assessing students' knowledge of key concepts. The first assignment contains three questions about Charles' Law, drawing structural formulas, and types of radioactive decay. The second assignment asks students to explain buffers and calculate pH. It also asks students to calculate the pH of a baking soda solution. The third assignment contains three questions asking students to describe heat transfer between substances, how calorimeters work, and using calorimetry data to calculate enthalpy of fusion.

1. Graded Assignment
SCI303B: Chemistry | Unit 9 | Lesson 4: Semester Test
Name:
Date:
Graded Assignment
Semester Test, Part 2
Answer the questions below. When you have finished, submit
this assignment to your teacher by the due date for full credit.
(5 points)
Score
1. What is Charles’s law?
· State the definition of the law in words.
· What are the assumptions of Charles’s law?
· Write mathematical equations that represent the law.
· What can you do with Charles’s law?
· Using a gas-filled balloon as an example, describe what
happens to the gas molecules that behave according to Charles’s
law.
Answer:
(5 points)
Score
2. Draw a structural formula for 3,4-hexene (C6H12), which has
a double bond between the number 3 and 4 carbons in the chain.

2. What class of compound is it, and what feature distinguishes it
as that class?
Answer:
(5 points)
Score
3. Besides the major types of radioactive decay, there are two
others: positron emission and electron capture.
· Compare and contrast positrons with electrons.
· Explain how positron emission works and how it causes
transmutations.
· Explain how electron capture works and how it causes
transmutations.
· Compare the transmutations caused by positron emissions and
electron capture.
Answer:
Score
(5 points)
4. A calorimeter contains 500 g of water at 25°C. You place a
hand warmer containing 200 g of liquid sodium acetate inside
the calorimeter. When the sodium acetate finishes crystallizing,
the temperature of the water inside the calorimeter is 39.4°C.
The specific heat of water is 4.18 J/g-°C. What is the enthalpy
Where necessary, use q = mHf.

3. Answer:
Your Score
___ of 20
© 2009 K12 Inc. All rights reserved.
Page 1 of 2
Copying or distributing without K12’s written consent is
prohibited.
Graded Assignment
SCI303B: Chemistry | Unit 3 | Lesson 11: Unit Test
Name:
Date:
Graded Assignment
Unit Test, Part 2
Answer the questions below. You may use a scientific calculator
for this test. When you have finished, submit this assignment to
your teacher by the due date for full credit.
(5 points)
Score
1. Explain what is in a buffer. Discuss the function of a buffer.
How will pH change when small amounts of acids or bases are
added to the buffer solution?
Answer:
(5 points)
Score
2. Cooks use baking soda to make cakes light and fluffy. You
might have used baking soda yourself. Baking soda is NaHCO3.
A 0.1 M solution of baking soda in water has a [H+] of about

4. 4.0 × 10–9. (You may prefer to think of the hydronium ion
concentration, [H3O+], as 4.0 × 10–9.) Write the formula for
the calculation of pH, and then show each step as you calculate
the pH of a 0.1 M solution of baking soda.
Answer:
(5 points)
Score
3. Before tackling this problem, be sure you know how to find
the antilog of a number using a scientific calculator.
A solution has a pH of 5.4. Write the formula you will use to
calculate the [H+] and then show all your work leading to the
determination of [H+].
Answer:
Your Score
___ of 15
© 2009 K12 Inc. All rights reserved.
Page 1 of 1
Copying or distributing without K12’s written consent is
prohibited.
Graded Assignment
SCI303B: Chemistry | Unit 4 | Lesson 8: Mid-Unit Test
Name:
Date:
Graded Assignment
Mid-Unit Test, Part 2
Answer the questions below. Unless otherwise instructed, you
may use a scientific calculator and refer to the periodic table in
the Chemistry: Problems and

5. Solution
s book for this test. When you have finished, submit this
assignment to your teacher by the due date for full credit.
(5 points)
Score
1. Describe what happens when two substances at different
temperatures come into contact. Describe how the law of
conservation of energy applies to this system.
Answer:
(8 points)
Score
2. You used a calorimeter in the Heat Transfer lab. Explain how
the calorimeter works, and how you can calculate the heat given
off or absorbed by the reaction being studied.
Answer:
(8 points)

6. Score
3. A calorimeter contains 500 g of water at 25°C. You place a
hand warmer containing 100 g of liquid sodium acetate (NaAC)
inside the calorimeter. When the sodium acetate finishes
crystallizing, the temperature of the water inside the calorimeter
is 32.2°C. The specific heat of water is
4.18 J/g-°C. What is the enthalpy of fusion (ΔHf) of the sodium
acetate? Show your work.
Answer:
Your Score
___ of 21
© 2009 K12 Inc. All rights reserved.
Page 1 of 1
Copying or distributing without K12’s written consent is
prohibited.