Question

An ideal gas is allowed to expand freely against vacuum in a rigid insulated container. The gas undergoes

• A. an increase in its internal energy
• B. a decrease in its internal energy
• C. neither an increase nor decrease in temperature or internal energy
• D. an increase in temperature

Answer 1

The correct option is C neither an increase nor decrease in temperature or internal energy

As the container is insulated , Q = 0

As it is expanding freely, the work done is zero.

$△$V = Q-W

$△$V = 0

$△$ = $C_V$$△$T

$\therefore$ $△$ = 0

Hence, there will be no increase or decrease in temperature or internal energy.