Question

A cylinder contains a gas at temperature of ${27}^{0}C$ and a pressure 1MPa. If the temperature of the gas is lowered to ${23}^{0}C$, the change in Pressure would be:

Answer 1

Charles' law states that at constant v,

$P\propto T$

$\Rightarrow \frac{△P}{P}=\frac{△T}{T}\to \left(1\right)$

Initially, $T={27}^{\circ }C$ and $P=1$ MPa, temp changes $△T=-4$

$\Rightarrow △P=\frac{△T}{T},P=\frac{-4}{300}\times {10}^6=-4\times {10}^4$ Pa

$\Rightarrow$ final pressure = $P+△P={10}^6-4\times {10}^4=9.6\times {10}^5$ Pa