How much heat energy is required to vaporize a 4.40-g ice cube at 0C? The heat of fusion of ice is 80.0 cal/g. The heat of vaporization of water is 540 cal/g, and cwater = 1.00 cal/g/C.
a. 2 730 cal
b. 3 170 cal
c. 2 820 cal
d. 3 520 cal
e. 2 380 cal
[Ques. 2] The heating coil of a hot water heater has a resistance of 17 and operates at 300 V. How long a time is required to raise the temperature of 115 kg of water from 18C to 75C? (The specific heat for water = 103 cal/kgC and 1.0 cal = 4.186 J).
a. 1.5 h
b. 1.9 h
c. 0.45 h
d. 1.4 h
e. 0.50 h
[Ques. 3] I take 2.0 kg of ice and dump it into 2.3 kg of water and, when equilibrium is reached, I have 4.3 kg of ice at 0C. The water was originally at 0C. The specific heat of water = 1.00 kcal/kg/C, the specific heat of ice = 0.500 kcal/kg/C, and the latent heat of fusion of water is 80.0 kcal/kg. The original temperature of the ice was
a. one or two degrees below 0C.
b. 46.0C.
c. 184C.
d. 184C.
e. The whole experiment is impossible.
[Ques. 4] A steam turbine at an electric power plant delivers 4 500 kW of power to an electrical generator which converts 94 of this mechanical energy into electrical energy. What is the current delivered by the generator if it delivers at 3 500 V?
a. 7.3E+2 A
b. 1.4E+3 A
c. 1.2E+3 A
d. 1.1E+3 A
e. 8.3E+2 A
[Ques. 5] In cloud formation, water vapor turns into water droplets which get bigger and bigger until it rains. This will cause the temperature of the air in the clouds to
a. get warmer.
b. get cooler.
c. will not affect the temperature of the air in the clouds.
d. There is no air in clouds.
[Ques. 6] An electric clothes dryer draws 10 A at 220 V. If the clothes put into the dryer have a mass of 10 kg when wet and 3 kg dry, about how long does it take to dry the clothes? (Assume all heat energy goes into vaporizing water, Lv = 2.26 106 J/kg).
a. 171 min
b. 120 min
c. 51 min
d. 40 min
e. 5 min
[Ques. 7] 125 g of dry ice (solid CO2) is dropped into a beaker containing 600 g of 64.0C water. The dry ice converts directly to gas, leaving the solution. When the dry ice is gone, the final temperature of the water is 33.2C. What is the heat of vaporization of solid CO2? (cwater = 1.00 cal/g/C)
a. 160 cal/g
b. 142 cal/g
c. 118 cal/g
d. 148 cal/g
e. 154 cal/g
[Ques. 8] A light bulb, sold as long-lasting, is rated 95 W at 145 V. The increased lifetime comes from using it at 110 V. Assuming negligible change in resistance at the different voltage, what is its power consumption at 110 V?
a. 55 W
b. 170 W
c. 190 W
d. 47 W
e. 110 W
[Ques. 9] A 35.0-g cube of ice, initially at 0.0C, is dropped into 180.0 g of water in an 70.0-g aluminum container, both initially at 35.0C. What is the final equilibrium temperature? (Specific heat for aluminum is 900 J/kg/C, the specific heat of water is 4 186 J/kg/C, and Lf = 3.33 105 J/kg.)
a. 35.1C
b. 17.6C
c. 8.79C
d. 26.4C
e. 30.8C
[Ques. 10] An electric toaster requires 1 300 W at 150 V. What is the resistance of the heating coil?
a. 2.9
b. 74
c. 34
d. 17
e. 38
Quick Reply
