A sample of helium has a volume of 325 mL and a pressure of 655 mm Hg. What will be the pressure if the helium is compressed to 125 mL?

Nov 29, 2015

The pressure at $\text{125 mL}$ will be $\text{1703 mmHg}$.

Explanation:

This is an example of Boyle's law, which states that the volume of a given amount of gas at constant temperature, varies inversely with the pressure. The equation is ${P}_{1} {V}_{1} = {P}_{2} {V}_{2}$

Given/Known
Pressure 1: $\text{655 mL Hg}$
Volume 1: $\text{325 mL}$
Volume 2: 125 mL"

Unknown
Pressure 2: ${P}_{2}$

Solution
Rearrange the equation to isolate ${P}_{2}$ and solve.

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

P_2=((655"mm Hg"xx325cancel"mL"))/(125cancel"mL")="1703 mmHg"