Question

An ideal gas expands while the pressure is kept constant. During the process, does heat flow into the gas or out of the gas? Justify you answer.

Answer 1

The pressure is constant and it is ideal gas which means:

• PV=nRT
• Here P, R, n are constant which means V∝T
• As the gas expands means T is increasing let say it is ΔT>0.
• Now the heat flow in the system is identified by the formula
• Q=nCpΔT
• Therefore from above value Q>0
• Therefore there is absorbance which means the heat flow is inward or into the gas.