Chapter 20, Problem 30SP

A sealed chamber containing 32.5 g of molecular oxygen and 20.2 g of molecular nitrogen at 48.0 °C is cooled down to 20.2 °C. Given that for ${\text{N}}_2,c_{\upsilon }=0.743\text{ kJ/kg}\cdot \text{K}$, and for ${\text{O}}_{\text{2}}$, $c_{\upsilon }=0.659\text{ kJ/kg}\cdot \text{K}$, determine the resulting change in the internal energy of the gas.