1) An auditorium has dimensions 10 m by 22 m by 44 m. How many moles of air occupy the auditorium at 1 atm and 15 C? The value of the universal gas constant is 8.31451 J/K mol. Answer in units of mol

2) A building made with a steel structure is 897 m high on a winter day when the temperature is 0F. How much taller is the building when the temperature is T = 115F? The linear expansion coefficient of steel is 1.1 105 ( C)1 . Answer in units of cm.

3) A bridge is made with segments of concrete 109 m long (at the original temperature). If the linear expansion coefficient for concrete is 1.2 105 ( C)1 , how much spacing is needed to allow for expansion for an increase in temperature of 45F? Answer in units of cm.

4) 5 mol of an ideal gas is kept at 890C in an expansion from 1 L to 5 L . How much work is done by the gas? The universal gas constant is 8.31 J/K/mol . Answer in units of J.

5) At 40 m below the surface of the sea (density of 919 kg/m3 ), where the temperature is 7 C, a diver exhales an air bubble having a volume of 0.9 cm3 . The acceleration of gravity is 9.8 m/s 2 . If the surface temperature of the sea is 12C, what is the volume of the bubble immediately before it breaks the surface? Answer in units of cm3 .

6) A heat engine operates between two reservoirs at 31.4 C and 169C. What is the maximum efficiency possible for this engine?

7) Water will boil spontaneously in a vacuum (on the moon, for example). Could you cook an egg in this boiling water? Why?

1. No; the water temperature is low.

2. No; the boiling of water in this condition is not very intense.

3. Yes; the bubbing of the surrounding water cooks the egg.

4. Yes; water that boils will always cook the egg

8) In each cycle, an engine removes 170 J from a reservoir at 100 C and gives off 140 J to a reservoir at 12 C. What is the efficiency of this engine?

B) What is the ratio of its efficiency to that of a Carnot engine working between the same reservoirs