Question

The pressure of 5.0 l of gas increases from 1.50 atm to 1240 mmhg. what is the final volume of the gas, assuming constant temperature?

Answer 1

First we need to convert everything into SI units.

The initial volume of the gas is (keeping in mind that $1 L = 0.001 m^3$:
$V_i = 5.0 L = 0.005 m^3$

The initial pressure of the gas is (keeping in mind that $1 atm = 1.01 \cdot 10^5 Pa$:
$p_i = 1.50 atm=1.52 \cdot 10^5 Pa$

The final pressure of the gas is (keeping in mind that $760 mmHg = 1 atm=1.01 \cdot 10^5 Pa$)
$p_f = 1240 mmHg = 1.65 \cdot 10^5 Pa$

At constant temperature, the product between pressure and volume of the gas is constant, so we can write
$p_i V_i = p_f V_f$

from which we find the final volume of the gas:
$V_f = \frac{p_i V_i}{p_f} = \frac{(1.52 \cdot 10^5 Pa)(0.005 m^3)}{1.65 \cdot 10^5 Pa} =0.0046 m^3 = 4.6 L$