Suppose a heat engine is connected to two energy reservoirs, one a pool of molten aluminum (660°C) and the other a block of solid mercury (-38.9°C). The engine runs by freezing 1.00 g of aluminum and melting 15.0 g of mercury during each cycle. The heat of fusion of aluminum is 3.97 x105 J/kg; the heat of fusion of mercury is 1.18 x 104 J/kg. What is the efficiency of this engine?

An ideal gas is heated at a constant pressure of 1.80 x 10 Pa from a temperature of -73.0°C to a temperature of +27.0°C. The initial volume of the gas is 0.100 m³. The heat energy supplied to the gas in this process is 40.0 kJ. What is the increase in internal energy of the gas? -8.95:kJ

An uninsulated container holds 3.5 mol of an ideal gas at an initial temperature of 300 K. The gas is compressed by a movable piston, and 500 J of work is done on the gas while being compressed. If the final temperature of the gas is 400 K, how much heat flows in or out of the gas during this process?

A 155 g copper bowl contains 230 g of water, both at 20.0°C. A very hot 300 g copper cylinder is dropped into the water, causing the water to boil, with 4.05 g being converted to steam. The final temperature of the system is 100°C. Neglect energy transfers with the environment. (a) How much energy (in calories) is transferred to the water as heat? 8.6 X kcal (b) How much energy (in calories) is transferred to the bowl? 55 X kcal (c) What is the original temperature of the cylinder? 553.6 X °C Did you use the idea of conservation of energy? That is, did you equate the sum of the energy transfers to zero? For the bowl and cylinder, did you substitute the expression relating an energy transfer, the specific heat, the mass, and the temperature change? For the water, did you use the same expression to get the water to the boiling point? Did you also include an expression for the heat of vaporization? Did you use the given final temperature for each of the three materials?