Question

Convert 77.0 L at 18.0 mm of Hg to its new volume at standard pressure.

Answer 1

The answer is `1.8L`.

Standard Temperature and Pressure stipulates a pressure of `100.0kPa`. In order to solve this problem, we'll use Boyle's law, `P_1V_1 = P_2V_2`, which states that the pressure and volume of a gas are proportional to one another.

Let's calculate the volume by converting `mmHg` to `kPa` first.

`18 mmHg * (1.0 atm)/(760 mmHg) * (101.325 kPa)/(1.0 atm) = 2.4kPa`

So, `V_2 = P_1/P_2 * V_1 = (2.4 kPa)/(100.0 kPa) * 77L = 1.8L`

Now calculate the volume by converting `kPa` to `mmHg`.

`100.0 kPa * (1 atm)/(101.325 kPa) * (760 mmHg)/(1 atm) = 750 mmHg`

`V_2 = P_1/P_2 * V_1 = (18 mmHg)/(750 mmHg) * 77L = 1.8L`