Name: _____________________
Unit One Heat: Review
** For your test, you will be allowed one single-sided 8.5 x 11 cheat sheet. You can write
whatever you like on it but it must be handwritten (not computer generated or using some
kind of special pen or whatever kind of crazy mojo you can think of). IF YOU DO NOT
FOLLOW THE RULES, I WILL SIMPLY REMOVE YOUR CHEAT SHEET AND YOU CAN WRITE THE
EXAM WITHOUT IT.
I will provide you with the following tables on your exam. You will be responsible for
understanding how to use them and any other information not on these tables.
- Coefficients of Thermal Expansion
- Specific Heat Capacities of Various Materials
- Latent Heat Values
** Make sure to show your work for every question for full marks! Round all answers to two
decimal places unless otherwise stated. Also leave answers in scientific notation (except for
temperature).
1. Convert .000 025 48 to scientific notation.
2. Convert the temperatures from Celsius to Kelvin.
a. 27C
b. 560C
c. -184C
Name: _____________________
3. Convert the temperatures from Kelvin to Celsius
a. 110 K
b. 22 K
c. 402 K
4. Explain the difference between heat and temperature. How are they related?
5. What happens to molecules of a substance as the substance is heated?
Name: _____________________
6. Define:
a. Convection
b. Conduction
c. Radiation
7. A steel beam which is 12.0 m in length sits next to a concrete wall when the
temperature is 20.0C. A gap must be left between the beam and the concrete wall for
expansion purposes. If the temperature rises to 45.0C, how large must the gap be if
the steel beam just touches the concrete wall?
8. What is the final length of a 6.00 m aluminum rod if the temperature changes from
410 K to 250 K?
Name: _____________________
9. A beaker is filled to the brim with 250 mL of ethyl alcohol at 15°C. How much will
overflow at 30.0°C? (Assume that the beaker does not expand significantly.)
10. What is latent heat?
11. 2.52 x 104 J of heat are added to 2.0 kg of mercury to reach a final temperature of
130C. What was the initial temperature of the mercury?
12. Determine the temperature change when 400 g of water gains 9400 J of heat
Name: _____________________
13. Determine the specific heat capacity if 2.5 kJ of heat removed from 160 g of iron cools it
from 100°C to 52°C
14. A 25.0 g bolt made of an alloy absorbed 250 J of heat as its temperature changed from
25.0°C to 78.0°C. What is the specific heat capacity of the alloy?
15. How many joules of heat are lost by 3580 kg of granite as it cools from 41.2°C to 12.9°C.? The specific heat of granite is 803 J/kg°C.
Name: _____________________
16. When 10.2 g of canola oil at 25.0 °C is placed in a wok, 3.34 kJ of heat is required to heat
it to a temperature of 196.4°C. What is the specific heat of canola oil?
17. What is the change in heat as 10.0 kg of water at 25.0°C turns to ice at -13.0°C?
Name: _____________________
18. How much heat is needed to change 0.10kg of ice at –20⁰C to steam at 110⁰C?
Name: _____________________
19. How much heat is needed to change 2.0 kg of silver at 20⁰C into liquid silver? Silver
melts at 961⁰C.
20. 0.100 kg of an unknown metal at 94⁰C is placed in 100 grams of water at 10⁰C. The final
temperature of the metal and water are 17⁰C. What is the heat capacity of the
unknown metal?
Name: _____________________
21. A 125 g pyrex class mug at 20⁰C is filled with 200 g of Tim’s coffee at 90⁰C. Assuming
that all heat lost by the Tim’s coffee is transferred to the mug, what will be the final
temperature of the Tim’s coffee? (Assume coffee to have the same specific heat
capacity of water)
22. A 0.100 kg piece of metal is heated to 480⁰C and then quickly placed in 0.250 kg of
water at 20⁰C which is contained in a 0.200 kg aluminum calorimeter. The final
temperature of the water, metal and calorimeter is 36⁰C. What is the specific heat
capacity of the metal piece?
Name: _____________________
23. How does heat move?
24. Why is knowledge about heat transfer useful in industries (creating insulation, designing
blueprints, building homes/buildings, etc.)?
25. If iron changes from a solid to a liquid, is it an endothermic or exothermic reaction?
What happens to the molecules in the iron as this happens?
26. Distinguish between exothermic and endothermic reactions.
Name: _____________________
27. Compare the following reactions and answer the questions:
2 SO2 (g) + O2 (g)
→
2 SO3 (g)
Δ H = -197.8 kJ
i. Is this reaction endothermic or exothermic?
ii. Re-write this reaction where energy is part of the equation.
28. Compare the following reactions and answer the questions:
2 N2 (g) + O2 (g)
→
2 N2O (g)
Δ H = +163.2 kJ
i. Is this reaction endothermic or exothermic?
ii. Re-write this reaction where energy is part of the equation.
29. Given the following reaction, how much energy would be released if 52.3g of CO
reacted?
2CO (g) + O2 (g)
→
2 CO2 (g)
Δ H = -566.0 kJ
30. Given the following reaction, how much energy in joules would be released if 21.98g of
ethyne was produced?
2C(s) + H2(g)  C2H2 (g)
∆H = -227kJ
Name: _____________________
Some notes about making cheat sheets:
-
Do not put on information that you already know! It is a waste of precious space!
Unless you have lots of room I guess…
-
Put examples on your cheat sheet (especially of hard questions)
-
Explain what table uses what value (ex. Latent Heat table gives Hf and Hv)
-
Put information in order from beginning of unit to end of unit.
-
Colour code information?
-
USE THE ENTIRE SPACE! DO NOT LEAVE GAPS ON YOUR CHEAT SHEET. THE MORE
THAT IS ON IT, THE GREATER THE CHANCE YOU WILL BE SUCCESSFUL ON THIS EXAM.
-
Become familiar with your cheat sheet. Once you make it, try out a couple questions
and see if you need to add or change any information.
Answers:
1. 2.55 x 10-5
2. a. 300 K
b. 833 K
c. 89 K
3. a. -163⁰C
b. -251⁰C
c. 129⁰C
4. ** See notes
5. ** See notes
6. ** See notes
7. 3.6 x 10-3 m or 3.6 mm wide
8. 5.99 m
9. 4.13 x 10-3 L or 4.13 mL
10. ** See notes
11. 40⁰C
12. 5.62⁰C
13. 3.26 x 102 J/kg⁰C
14. 1.89 x 102 J/kg⁰C
15. 1.56 x 108 J removed or -1.56 x 108 J
Name: _____________________
16. 1.91 x 103 J/kg⁰C
17. 4.62 x 106 J removed or -4.62 x 106 J
18. 3.11 x 105 J
19. 6.09 x 105 J
20. 3.8 x 102 J/kg⁰C
21. 82.69⁰C
22. 4.41 x 102 J/kg⁰C
23. ** See notes
24. ** May vary (check with me if you are unsure)
25. Iron takes in heat = endothermic
26. ** See notes
27. a. exothermic
b. 2 SO2 (g) + O2 (g)
→
2 SO3 (g)
+
197.8 kJ
28. a. endothermic b. 2 N2 (g) + O2 (g)
+
163.2 kJ
→
2 N2O (g)
29. 5.28 x 102 kJ
30. -1.92 x 102 kJ