Chemistry Spring Semester
Honors Chemistry Unit 4 Test Study Guide
Instructions:
** This study guide is intended to HELP you to study for the unit test, but it is not comprehensive. You
should have read each lesson, completed the practice problems and quizzes and attended the class
connect sessions before taking the test.
Additional resource:
The link to a website with practice worksheets and answer keys:
http://misterguch.brinkster.net/gaslawworksheets.html
Come to a help session BEFORE the test if you can’t answer any of these questions!
Lesson 1: Conservation of Energy
1. Define: Exothermic
2. Define: Endothermic
3. Solid ice absorbs heat energy to become liquid water. What type of reaction is this and why?
4. Where does the energy released from an exothermic reaction come from?
5. What phase changes are exothermic?
6. Give examples of exothermic chemical reactions.
7. What phase changes are endothermic?
8. Give examples of endothermic chemical reactions.
9. What is the law of conservation of energy?
Lesson 2: Measuring the Flow of Heat
1. Define: Thermal Energy
2. Define: Heat
3. Describe heat in terms of the kinetic energy of the particles of a substance.
4. What is the difference between thermal energy, temperature and heat?
5. How is heat transferred between objects?
6. If a “hot” object is placed next to a “cold” object, which way does the heat flow?
7. What units are used in heat exchange measurements?
Lesson 3: Heat Transfer Lab (Complete Lessons 5 & 6 BEFORE completing this lab!)
Chemistry Spring Semester
Honors Chemistry Unit 4 Test Study Guide
1. What are the goals of this lesson/lab?
2. What is a calorimeter?
3. Define: Specific Heat Capacity
4. What equation is used to calculate heat released?
5. Define: Enthalpy of fusion
6. What does enthalpy of fusion tell you about a substance?
7. How is enthalpy of fusion calculated?
8. Bonus: Describe the parts of a coffee-cup calorimeter and how it works. (You will need to look
this up on the internet)
9. Bonus: What “variable” is held constant in a coffee-cup calorimeter? (you will need to look this
up on the internet)
Lesson 5: Specific Heat (Complete this lesson before the lab!)
1. Define: Heat Capacity
2. Define: Specific Heat
3. What is “C”?
4. A 50 g copper rod absorbs 585 J of heat to raise its temperature by 30°C. What is the specific
heat of copper?
5. How do you calculate the amount of heat released from a substance?
6. If a substance has a high specific heat, what does this mean about the substance’s ability to
absorb heat?
7. What kind of liquid (high or low specific heat) would be best used as a coolant?
Lesson 6: Changes in Enthalpy (Complete this lesson before you complete the lab!)
1. Define: Enthalpy
2. What does H stand for?
3. What is the sign of the H of an endothermic reaction?
4. What is the sign of the H of an exothermic reaction?
5. If the H of a reaction is a given value, what is the H of the reverse reaction?
Chemistry Spring Semester
Honors Chemistry Unit 4 Test Study Guide
6. Be able to calculate H.
7. Define: Latent Heat
8. Draw and label all of the parts of the energy diagram on slide #10. Be sure you
understand what is happening at each part.
Lesson 9: Thermochemical Equations
1. Define: Thermochemical equation
2. What are the requirements of a correctly written thermochemical equation?
3. Give an example of a correctly written thermochemical equation and label the parts.
4. Work through each practice problem in the lesson (there are some additional problems at the
bottom of this study guide).
Lesson 10: Heat & Changes of State
1. Define “Enthalpy of fusion”
2. What other terms are used for “enthalpy of fusion”?
3. Define Enthalpy of Vaporization
4. Define Heat of Condensation
5. Draw and identify the parts of a heat diagram.
6. Understand the parts of the diagram and how energy is involved in each phase change.
7. Work through the sample problem and be able to do similar problems.
Lesson 11: Hess’s Law
1. Define: Hess’s Law
2. By using the following reactions, calculate the H of the reaction: -566kJ
Overall reaction= 2CO(g) + O2(g)  2CO2(g)
C(s) + O2(g)  CO2 (g) H=-393.5kJ
C(s) + ½O2(g)  CO(g) H=-110.5kJ
3. You have a series of four chemical reactions (1,2,3,4). How do you calculate
the H3 if you know the other H values?
Additional Practice Problems using info from the whole unit:
1. How is the energy of the reactants related to the energy of the products in an endothermic
reaction?
Chemistry Spring Semester
Honors Chemistry Unit 4 Test Study Guide
2. How is the energy of the reactants related to the energy of the products in an exothermic
reaction?
3. In a calorimeter, 50 g of ice melts at 0oC. The enthalpy of fusion of the ice is 334
J/g. How much heat was absorbed? 16.7 kJ
4. How much heat do you need to raise the temperature of 200 g of ice from -40oC to
-10oC? 12.3kJ
5. In a calorimeter, 16.7kJ of heat was absorbed by 50 g of ice. What is the enthalpy of
fusion of the ice? q = mHf 334 J/g
6. If 5.6 kJ of energy is added to 100 g of Aluminum at 125oC, what is the final
temperature in degrees Celsius? (Specific heat Aluminum=0.90J/g oC) 187.2oC
7. The reaction 2CO(g) + O2(g)  CO2(g) has a H=-566.6 kJ. How much heat will be
required to produce 44.8L of CO by the reverse reaction? +566.6 kJ
8. Describe an enthalpy diagram. What does an enthalpy diagram look like for an
endothermic reaction? An exothermic reaction?
9. How much heat is given off when 23 g liquid ethanol (CH3CH2OH) at its freezing point
changes to solid ethanol? (ethanol Hf = 4.9 kJ/mol) 2.45kJ
10. What is the change in enthalpy when 200 g of methanol condenses? (Hv = 35.278
kJ/mol) 220kJ
11. How much methanol freezes to release 20 kJ of heat (Hf = 3.21 kJ/mol)? 6.2mole
or 198g CH3OH.