Let's assume that volume of the gas is a constant.
We can use Gay-lussac's pressure temperature law to solve this problem.
It says the pressure of a given amount of gas is directly proportional to its temperature in Kelvin when the volume is a constant.
P α T
Where P is the pressure and T is the temperature in Kelvin of the gas. We can use this for two situations as, P₁/T₁ = P₂/T₂
P₁ = 0.456 atm T₁ = 275 KP₂ = 845 mmHg = 1.112 atm T₂ = ?
By applying the formula,
0.456 atm / 275 K = 1.112 atm / T₂ T₂ = (1.112 atm / 0.456 atm) x 275 K
T₂ = 670.6 K
Hence, the temperature of the hydrogen gas is 670.6 K