Take Home Exam: Heat and Temperature

 Heat and Temperature

1. A 16.6 g piece of metal (specific heat of 0.293 cal/g-ºC) is warmed so that its temperatre increases by 6.43ºC. How much heat (in calories) was transferred into it?
2. A window pane 0.334 cm thick has an area of 1.024 square meters. The temperature difference between the inside and outside surfaces of the window is 10.5 ºC . What is the rate of heat flow through this window in J/s if the thermal conductivity for glass is 0.8 J/s-m-ºC?
3. How many kilowatt hours of energy are required to raise the temperature of 26950 gal of water by 5.88ºC? One gal of water has a mass of about 3.8 kg and the specific heat of water is 4186 J/kg-ºC.
4. How many kg of ice need to be added to 2.54 kg of water at 73.1ºC to cool the water to 14.4ºC? (Lf = 80 kcal/kg)
5. An engine exhausts 3799 J of heat while performing 1125 J of useful work. What is the per cent efficiency of the engine?