Hw 10: Laws of Thermodynamics 10.1) [12.21 in text book] An ideal monatomic gas expands isothermally from 0.500 m3to 1.25 m3at a constant temperature of 675 K. The initial pressure of the gas is 1.00 105P a. a) Find the work done on the gas. [4.58 104J] b) Find the thermal energy transfer, Q.[+4.58 104J] c) Find the change in the internal energy.

10.2) [12.26 in text book] One mole of gas initially at a pressure of 2.00 atm and a volume of 0.300 L has an internal energy equal to 91.0 J. In its final state, the gas is at a pressure of 1.50 atm and a volume of 0.8800 L, and its internal energy equals 182 J. For the paths IAF , IBF , and IF in the below figure, calculate: a) The work don on the gas. b) The net energy transferred to the gas by heat in the process.

10.3) [12.37 in text book] An engine absorbs 1.70 kJ from a hot reservoir at 277C and expels 1.20 kJ to a cold reservoir at 27C in each cycle. a) What is the engine's efficiency? [e = 0.29] b) How much work is done by the engine in each cycle? [0.5 kJ] c) What is the power output of the engine if each cycle lasts 0.300 s? [1666W atts]

10.4) [12.46 in text book] A 65 g ice cube is initially at 0.0C. a) Find the change in entropy of the cube after it melts completely at 0.0C.[79.24 J/K] b) What is the change in entropy of the environment in this process? Hint: the latent heat of fusion for water is 3.33 105J/kg.

10.5) [12.50 in text book] If you roll a pair of dice, what is the total number of ways which you can obtain a) a 12? b) a 7? c) Which dice roll is more probable? Equivalently: which state has higher entropy? S ln(P)