PHYSICS 11 HEAT WORKSHEET 2
Read over your notes on heat, and refer to Chapter 12 (Tables 12-1 and 12-2) of the text in
order to answer the following questions.
1.
How much heat is lost in cooling 0.600 kg of water (sp. heat = 4180 J/kg C) from 90 C
to 40 C?
2.
How much heat is required to raise the temperature of 1.00 kg of aluminum (sp. heat =
903 J/kg C) from 20 C to 65 C?
3.
a) The radiator of a car is designed to remove thermal energy from the car engine.
If 7.00 x 105 J of energy are removed from the engine by 17.4 kg of water in the
radiator, by how much will the temperature of the water rise?
b) If the same amount of energy was removed by 17.4 kg of methanol (the primary
ingredient in antifreeze), by how much would the temperature of the methanol rise?
4.
A physics teacher wants to add 1.8 x 104 J of energy to his cold mug of coffee by nuking it.
If the coffee contains 0.150 kg of water and currently sits at 18.2 C, what will its
temperature be when pulled from the microwave oven?
5.
Which will be more painful: holding 10.0 g of water at 95 C, or 10.0 g of lead at the same
temperature? Assume each material is held until it reaches skin temperature of 34 C, and
explain your answer with calculations.
6.
at
A thermos bottle contains 0.150 kg of water at 4.0 C. When 0.090 kg of a metal, initially
100 C, is put into the water, the temperature of the water rises to 21 C. Calculate:
a) the thermal energy gained by the water; b) the specific heat of the metal.
7.
A 700 watt submersible electric heater is used to heat a beaker containing 1.20 kg of water.
How long will it take to heat up the water from 15 C to 95 C?
8.
A 2000 W kettle heats 2.0 kg of water from 22 C to 42 C in 120 s.
a) What is the amount of input energy?
b) What is the amount of output energy?
c) What is the % efficiency of the electric kettle?
9.
Examine Fig. 12-14 on p. 254 of the text. Which has more heat: 500 g of water at 100 C,
or 500 g of steam at the same temperature? Explain your answer.
10.
An ice cube tray containing 0.47 kg of ice at –8.6 C is left out of the freezer until it melts
and warms to 15 C. How much thermal energy was gained:
a) as the ice melted?
c) as the water warmed?
b) during the phase change?
d) in total?
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1. 1.25 x 10 J 2. 4.06 x 10 J 3. a) 9.6 C b) 16.4 C 4. 46.9 C 5. the water: 2550 J transferred whereas lead: only
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5
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79.3 J 6. a) 1.07 x 10 J b) 1500 J/kg C 7. 573 s 8. a) 2.4 x 10 J b) 1.67 x 10 J c) 70% 9. the steam - more heat
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contained in gas due to phase change 10. a) 8.3 x 10 3 J b) 1.6 x 10 J c) 2.9 x 104 J d) 1.9 x 105 J