Final answer:
When the valves are opened, the carbon dioxide and argon gases will diffuse and mix together. The combined pressure will be the sum of their individual pressures.
Step-by-step explanation:
When the valves are opened between the chambers, the gases will diffuse and mix together. The combined pressure of the carbon dioxide and argon after they diffuse will be the sum of their individual pressures.
According to Dalton's Law of partial pressures, the total pressure of a gas mixture equals the sum of the partial pressures of the individual gases. Therefore, the combined pressure of carbon dioxide and argon will be the sum of their pressures.