In a system composed of gas contained in a cylinder fitted with a piston,an adiabatic expansion causes the temperature of the gas to drop because
A)heat is given up by the system when the piston moves.
B)the pressure of the gas remains constant.
C)work is done on the system as the gas expands.
D)work done by the system is entirely at the expense of its internal energy.
E)heat is absorbed by the piston when it does work.

Question

Quizplus · Accepted Answer

An adiabatic process is one in which no heat is exchanged between the system and the surroundings. Therefore, the drop in temperature of the gas must be due to the work done by the system. In an adiabatic expansion, the gas performs work on the piston, and as a result, the internal energy of the gas decreases. This work is done entirely at the expense of the internal energy of the gas, hence the correct choice is D.

In a System Composed of Gas Contained in a Cylinder