Chapter 1, Problem 1.12NP

A rigid vessel of volume $0.\text{4}00{\text{ m}}^{\text{3}}$ containing ${\text{H}}_{\text{2}}$ at $\text{21}.\text{25}°\text{C}$ and a pressure of $\text{715}\times \text{1}{0}^{\text{3}}\text{Pa}$ is connected to a second rigid vessel of volume $0.\text{75}0{\text{ m}}^{\text{3}}$ containing Ar at $\text{3}0.\text{15}°\text{C}$ at a pressure of $\text{2}0\text{3}\times \text{1}{0}^{\text{3}}\text{Pa}$. A valve separating the two vessels is opened and both are cooled to a temperature of $\text{12}.\text{2}°\text{C}$. What is the final pressure in the vessels?