Question

1)A gas is compressed at a constant pressure of 0.800 atm from 8.00 L to 1.00 L. In the process, 410 J of energy leaves the gas by heat. (a) What is the work done on the gas? J

(b) What is the change in its internal energy? J

2) A gas increases in pressure from 2.00 atm to 6.00 atm at a constant volume of 1.00 m³ and then expands at constant pressure to a volume of 3.00 m³ before returning to its initial state as shown in the figure below. How much work is done in one cycle?
kJ

3) An engine absorbs 1.66 kJ from a hot reservoir at 277°C and expels 1.21 kJ to a cold reservoir at 27°C in each cycle.

(a) What is the engine's efficiency? %

(b) How much work is done by the engine in each cycle?   J

(c) What is the power output of the engine if each cycle lasts 0.298 s? kW

Answer 1

(1) W = P∆V

a)

W = (0.800 atm)(101.325 kPa/atm)(7 L)( 1m^3/1,000 L)

W ≈ 567.42 J

b)

∆U = 567.42 J - 410 J = 157.42 J