Question

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?

Answer 1

The pressure at `"125 mL"` will be `"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_1V_1=P_2V_2`

Given/Known
Pressure 1: `"655 mL Hg"`
Volume 1: `"325 mL"`
Volume 2: `125 mL"`

Unknown
Pressure 2: `P_2`

Solution
Rearrange the equation to isolate `P_2` and solve.

`P_2=(P_1V_1)/V_2`

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