b. DU = Q - W = (1400 kcal)((4186 J/1 kcal) - 6.262x105 J = 5.2 x 10⁶J

Problem 3

The pressure is given relative to the starting pressure, P₁ . Segment A is cooling at constant pressure. Segment B is the isothermal expansion.

Problem 18

The efficiency of a heat engine is e = W/Q_H = 9200 J/(22.0 kcal)(kcal/4186 J) = 10%

Problem 19

The maximum (Carnot) efficiency is       e = 1 - T_L/T_H = 23%         note that temperaure is in kelvins

Problem 29

The COF = T_L/T_H - T_L   for a refrigerator = 5.7       note that temperature is in kelvins

Problem 36

The heat added to the water is found from DQ = mcDT. We then use the averate temperature of 50 degrees C in the approximate entropy calculation.

DS = Q/T = mcDT/T = 1.30 x10³ J/K