Download 1 - Southwest High School

Specific Heat Practice Homework
Name ____________________________________________________Hour_________
For assistance with the following problems see your notes!!!
1. The heat formula is Q = m c  T.
Q
M
C
T
is the _________________ it can have units of _____________ (one example is ok).
is the _________________ it can have units of _____________ (one example is ok).
is the _________________ it can have units of _____________ (one example is ok).
is the _________________ it can have units of _____________ (one example is ok).
2.) A 5 g sample of metal with a specific heat of 350 c / g oC is heated and the
temperature changes by 10 oC. How much heat does the material gain?
In this question, what is the unknown variable? __________
In this question, what is the value for m ? __________
In this question, what is the value for c ? __________
In this question, what is the value for  T ? __________
3.) A 2 kg sample of lead is heated from a temperature of 30oC to a temperature of 60oC.
The specific heat of lead is 128 J / kg oC. How much heat energy did this sample absorb?
4.) A 2 kg sample of tin is heated from a temperature of 30.0 oC to a temperature of 30.92 oC.
The specific heat of water is 226 J / kg oC. How much heat energy did this sample absorb?
5.) Circle the correct answer:
Materials that have a high specific heat will have a (larger / smaller) change in
temperature when absorbing or releasing a certain quantity of heat than materials of equal
mass with a lower specific heat.
(Hint: In problems 3 and 4, the samples have the same mass and absorbed similar
amounts of heat. How did their  T values compare? They’re quite different!)
6.) The specific heat of copper is 390 J/kg oC. The specific heat of water is 4180 J/kg oC.
Which material will have a greater temperature change when you apply the same amount of
heat to equal masses of the substance?
7.) 5000 Joules of heat is applied to a piece of iron with a mass of 3kg. The temperature
changed by 3.55oC. What is the specific heat of Iron?
8.) The specific heat of lead is 130 J/kg oC. A sample of hot lead with an unknown mass
releases 4.5 kJ of its heat to a cup of water. The change in temperature of the lead is found to
be 2.5 oC. Calculate the mass of the lead. (You may need to convert between J and kJ)
9.) The heat of vaporization is the amount of heat required to change 1 kilogram of a pure liquid
substance into a vapor. The heat of vaporization of water is 2260 kJ/kg. That is, each
kilogram of boiling water that changes to steam must take in 2260 kJ of heat.
How much heat must be added (in kJ) in order to vaporize two kg of water?
10.) The heat of fusion is the amount of heat required to change 1kilogram of a pure solid
substance to liquid. The heat of fusion of water is about 334 kJ/kg. That is, ice at 0oC must
absorb 334 kJ of heat for each kilogram of ice that melts to liquid water at 0oC.
How much heat must be added (in kJ) in order to melt 800 grams of ice?
(Caution: What units of mass do you want to use? Do you need to convert?)
Answers
1) Q= quantity of Heat measured in joules or calories (kcal or kj, etc.)
m = mass measured in grams or kg
C = specific heat measured in cal/g oC or joules/ mole oC, etc
T = change in temperature measured in oC of Kelvin (K)
2) Q
5g
350 cal./g oC
10oC
3) 7680 joules
4) 16 joules
5) 523 joules
6) 300 grams
7) 20920 joules
8) 1840 joules
9) 0.21 j/g oC
10) 10.04oC
11) Smaller
12) Copper (metals are much easier to “heat up” than water; water has a HUGE specific
heat)
13) .469 j/g oC or 469 j/kg oC
14) 13.85 kg or 13,846 grams
15) 4520 kilojoules
16) 267.2 kilojoules
Answers (short page format0
1) Q= quantity of Heat measured in joules or calories (kcal or kj, etc.)
m = mass measured in grams or kg
C = specific heat measured in cal/g oC or joules/ mole oC, etc
T = change in temperature measured in oC of Kelvin (K)
2) Q
5g
350 cal./g oC
10oC
3) 7680 joules
4) 16 joule
5) 523 joules
6) 300 grams
7) 20920 joules
8) 1840 joules
9) 0.21 j/g oC
10) 10.04oC
11) Smaller
12) Copper (metals are much easier to “heat up” than water; water has a HUGE specific
heat)
13) .469 j/g oC or 469 j/kg oC
14) 13.85 kg or 13,846 grams
15) 4520 kilojoules
16) 267.2 kilojoules