A rigid tank contains a gas mixture with a specific heat of $c_{y}=0.748 \mathrm{~kJ} / \mathrm{kg} \cdot \mathrm{K}$. The mixture is cooled from $200 \mathrm{kPa}$ and $200^{\circ} \mathrm{C}$ until its pressure is $100 \mathrm{kPa}$. Determine the heat transfer during this process, in $\mathrm{kJ} / \mathrm{kg}$.