Question

12a. A 0.260-kg piece of aluminum that has a temperature of -159 °C is added to 1.0 kg of water that has a temperature of 2.7 °C. At equilibrium the temperature is 0 °C. Ignoring the container and assuming that the heat exchanged with the surroundings is negligible, determine the mass of water that has been frozen into ice. Number Units

b. If the price of electrical energy is $0.09 per kilowatt·hour, what is the cost of using electrical energy to heat the water in a swimming pool (12.0 m x 9.00 m x 1.50 m) from 12 to 26 °C?

Number

Units

dollarsm^3m^2kg/m^2F°

c. In an electrically heated home, the temperature of the ground in contact with a concrete basement wall is 12.0 ^oC. The temperature at the inside surface of the wall is 20.3 ^oC. The wall is 0.18 m thick and has an area of 6.7 m². Assume that one kilowatt hour of electrical energy costs $0.10. How many hours are required for one dollar's worth of energy to be conducted through the wall?

Number  Units

hrs

d. A wall in a house contains a single window. The window consists of a single pane of glass whose area is 0.11 m² and whose thickness is 6 mm. Treat the wall as a slab of the insulating material Styrofoam whose area and thickness are 17 m² and 0.15 m, respectively. Heat is lost via conduction through the wall and the window. The temperature difference between the inside and outside is the same for the wall and the window. Of the total heat lost by the wall and the window, what is the percentage lost by the window?

Percentage lost by window = Number  Units

W°CJ%°FmkgC°

Answer 1