Question

a sample of helium occupies a volume of 101.2 mL at a pressure of 790 mmHg. at what pressure would the volume be 120 mL?

Answer 1

Answer : The final pressure will be, 666.2 mmHg

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 = 790 mmHg

$P_2$ = final pressure = ?

$V_1$ = initial volume = 101.2 mL

$V_2$ = final volume = 120 mL

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

$790mmHg\times 101.2mL=P_2\times 120mL$

$P_2=666.2mmHg$

Therefore, the final pressure will be, 666.2 mmHg