Question

A stationary mass of gas is compressed without friction from an initial state of 0.3 m³ and 0.105 M Pa to a final state of 0.15 m³ and 0.105 M Pa. The pressure remaining constant. During the process there is transfer of 37.6 kJ of heat from the system. During the process the amount of internal energy change is-

• A. – 28. 85 kJ
• B. – 21.85 kJ
• C. – 21.85 MJ
• D. –53.35 kJ

Answer 1

Answer: (B)

– 21.85 kJ

Answer 2

DW = – 105 × (0.15 – 0.3) kJ = + 15.75 kJ

Dq = – 37 .6 kJ

\DE = DW + Dq = – 37.6 + 15.75 = – 21.85 kJ