A cylinder with a movable piston contains 4.00liters of a gas at 30°C and 5.00bar. The piston is slowly moved to compress the gas to 8.00bar.

(a) Considering the system to be the gas in the cylinder and neglecting ΔE_p, write and simplify the closed-system energy balance. Do not assume that the process is isothermal in this part.

(b) Suppose now that the process is carried out isothermally, and the compression work done on the gas equals 7.65L ∙ bar. If the gas is ideal so that U is a function only of T, how much heat (in joules) is transferred to or from (state which) the surroundings? (Use the gas-constant table in the back of the book to determine the factor needed to convert L ∙ bar to joules.)

(c) Suppose instead that the process is adiabatic and that U increases as T increases. Is the final system temperature greater than, equal to, or less than 30°C? (Briefly state your reasoning.)

Transcribed Image Text:

20 kg 4.50 Kg 1.40 g N2