Let’s solve a sample numerical problem (from the gas chapter) using Gay Lussac’s law or pressure law. The formula to be used is as follows: P1/T1 = P2/T2

**Example 1**

*A chamber of the constant volume contains hydrogen gas. When the chamber is immersed in a bath of* *melting ice (0°C), the pressure of the gas is 1.07 × 10*^{2}*kPa. What pressure will be indicated when* *the chamber is brought to 100°C ?*

**Solution: **T1=273 + 0 = 273 K*,*

*p*1=1.07 × 10^{2} *k*Pa =107 *k*Pa

T2=273 + 100 = 373 K,

*p*2 = ?

Since volume remains constant, therefore, according to Gay Lussac’s law: P1/T1 = P2/T2

=> P2 = (P1/T1)x T2 = 107 x 373 / 273 =1.462 x 10^{2} kPa

Numerical problems based on Gay Lussac’s law or pressure law