Question

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

Answer 1

Ideal gas equation : $PV=nRT$

$⟹$ $V\propto T$ for $P=constant$

As the gas in expanding i.e $V_2>V_1$ $⟹T_2>T_1$ OR $\Delta T>0$ .........(1)

Heat flow $Q=n{C}_p\Delta T$

$⟹$ $Q>0$ (from 1)

Thus the heat flows into the system.