Energy Efficiency Practice 3
Practice Problems
Directions: Answer the following questions on your own paper. Write the title of this assignment on the
top of your paper. SHOW ALL WORK (all 4 steps should be shown for each problem).
1. The element hydrogen has the highest specific heat of all elements. Hydrogen’s specific heat
capacity is 14300J/(kg ° C). If the temperature of a .34kg sample of hydrogen is to be raised by
25° C, how much heat will have to be transferred to the hydrogen?
2. Radon’s specific heat capacity is 94J/(kg° C). If the temperature of a 0.34kg sample of radon is to
be raised by 25° C, how much heat will have to be transferred to the radon?
3. A 0.59kg brass candle stick has an initial temperature of 98.0° C. If 21,100J of heat is removed
from the candle stick to lower its temperature to 6.8° C, what is the specific heat capacity of brass?
4. Mercury has one of the lowest specific heat capacities. If 257J of heat are added to 0.45 kg of
mercury, the mercury’s temperature will increase by 4.09 ° C. What is the specific heat capacity of
mercury?
5. A 0.38kg drinking glass is filled with a hot liquid. The liquid transfers 7032J of heat to the glass. If
the temperature of the glass increases by 22° C, what is the specific heat capacity of the glass?
6. The specific heat capacity of glass is 0.20 cal/(g° C). If 30 cal of heat are added to an unknown
mass of glass, the temperature raises by 150° C. What is mass of the glass?
7.What mass of water will give up 240 calories when its temperature drops from 80° C to 68° C.
8.If 216 J of energy is required to raise the temperature of aluminum from 15°C to 35° C, calculate
the mass of aluminum. (specific heat of aluminum is 0.90 J/( g° C)
9.The temperature of air in a foundry increases when molten metals cool and solidify. Suppose
9900000J of heat is added to the surrounding air by the solidifying metal. The air’s temperature
increases by 55, and the air has a specific heat capacity of 1000J/(kg ° C). What is the mass of the
heated air?
10.50 Joules of heat are added to a 2 kg block of iron. If the specific heat of iron is 452 J/(kg° C), how
much will its temperature increase?
11.A 30 g piece of iron is dropped into a container of water and gives off 165 calories in cooling.
Calculate the iron’s temperature change. (the specific heat capacity of iron is 0.11 cal/( g° C)
12.The initial temperature of 150 g of ethanol was 22° C. What would be the final temperature of the
ethanol if 3,240 J of energy were added? The specific heat capacity of ethanol is 2.44 J/ (g° C).