# The volume of 400 mL of chlorine gas at 400 mm Hg is decreased to 200 mL at constant temperature. What is the new gas pressure?

Jan 24, 2016

The new gas pressure is 800 mmHg.

#### Explanation:

This is an example of Boyle's law, which states that at constant mass and temperature, the volume of a gas is inversely proportional to the pressure.

The equation for Boyle's law is P_1V_1=P_2V_2".

Given
${V}_{1} = \text{400 mL}$
${P}_{1} = \text{400 mmHg}$
${V}_{2} = \text{200 mL}$

Unknown
${P}_{2}$

Solution
Rearrange the equation to isolate ${P}_{2}$. Substitute the given values into the equation and solve.

P_1V_1=P_2V_2"

${P}_{2} = \frac{{P}_{1} {V}_{1}}{V} _ 2$

P_2=((400"mmHg") * (400"mL"))/(200"mL")="800 mmHg"