Question

5. The volume of a sample of helium is 4.50 L at 20.0°C and 203.0 kPa. What will its volume be

Answer 1

The volume will be 2.25 L.

Explanation:

As per Charle's law, the volume of a gaseous system is directly proportional to the temperature provided the system is at constant pressure. Since volume of gas is directly proportional to the temperature of the gas molecules, V∝ T

So, in case there is a change in temperature with constant pressure, then there will be equal change in volume.

$\frac{V_{1}}{V_{2} } = \frac{T_{1}}{T_{2} }$

Thus, here $V_{1}$ = 4.50 L , $T_{1}$= 20 °C and $P_{1}$ = $P_{2}$ = 203 k Pa , $T_{2}$ = 10°C.

Since, volume and temperature is directly proportional then there will be increase in volume with increase in temperature and vice versa.

$\frac{4.50}{V_{2} } = \frac{20}{10}$

$V_{2} = \frac{4.50*10}{20} = 2.25 L$

So, the new volume is 2.25 L.