Question

The volume of a gas at 2.0 atm is 3.0 L. What is the volume of the gas at 1.5 atm at the same temperature?

Answer 1

Answer: The final volume of the gas comes out to be 4 L.

Explanation:

To calculate the volume with changing pressure, we use the equation given by Boyle's law.

This law states that pressure is inversely proportional to the volume of the gas at constant temperature and number of moles.

Mathematically,

$P\propto \frac{1}{V}$      (At constant temperature and number of moles)

The equation given by this law is:

$P_1V_1=P_2V_2$

where,

$P_1\text{ and }V_1$ are initial pressure and volume.

$P_2\text{ and }V_2$ are final pressure and volume.

We are given:

$P_1=2.0atm\\V_1=3L\\P_2=1.5atm\\V_2=?L$

Putting values in above equation, we get:

$2atm\times 3L=1.5atm\times V_2\\\\V_2=4L$

Hence, the final volume of the gas will be 4 L.

Answer 2

Answer : The correct option is, 4.0 L

Explanation :

Boyle's Law : It is defined as the pressure of the gas is inversely proportional to the volume of the gas at constant temperature and number of moles.

$P\propto \frac{1}{V}$

or,

$P_1V_1=P_2V_2$

where,

$P_1$ = initial pressure of gas = 2.0 atm

$P_2$ = final pressure of gas = 1.5 atm

$V_1$ = initial volume of gas = 3.0 L

$V_2$ = final volume of gas = ?

Now put all the given values in the above equation, we get:

$2.0atm\times 3.0L=1.5atm\times V_2$

$V_2=4.0L$

Therefore, the final volume of the gas is 4.0 L.