Question

A gas occupies 12.3 L at a pressure of 40 mmHg. What is the volume when the pressure is increases to 60 mmHg?

Answer 1

Step 1 - Understanding the relation between pressure and volume

There are three main variables that can modify the state of a gas: pressure (P), temperature (T) and volume (V). When one of them is kept constant, linear relationships arise between the other two variables, i.e., proportionality relations.

When the temperature is kept constant (isothermic transformation), the pressure and the volume become inversely proportional, i.e., increasing the pressure reduces the volume.

We can state it mathematically as:

`P_1V_1=P_2V_2`

Step 2 - Using the equation to solve the exercise

To calculate the new volume (V2), we can use the equation. The values we need are given in the exercise:

Substituting these values in the equation above, we have:

`\begin{gathered} 12.3*40=x*60 \\ \\ x=(12.3*40)/(60)=8.2L \end{gathered}`

The final volume would be thus 8.2L.