A sample of octane in equilibrium with its vapor in a closed 1.0-L container has a vapor pressure of 50.0 torr at 45°C. The container's volume is increased to 2.0 L at constant temperature and the liquid/vapor equilibrium is reestablished. What is the vapor pressure?

50 torr

Explanation:

Given:

Initial volume of the octane sample = 1.0 L

Initial vapor pressure = 50.0 torr

Increased volume = 2.0 L

Now, according the condition given in the problem the vapor pressure will be 50 torr for 2.0 L sample

The vapor pressure is same for the 2.0 L sample because, the temperature is remained constant and the vapor pressure does not depend on the volume of the sample.