Question

When the pressure that a gas exerts on a sealed container changes from 22.5 psi to psi the temperature changes from 110 c to 65.0 c

Answer 1

Gay- Lussacs law states that the pressure of a gas is directly proportional to temperature for a fixed amount of gas at constant volume.
therefore P/T = k
where P - pressure , T - temperature and k - constant 
$\frac{P1}{T1} = \frac{P2}{T2}$
parameters for the first instance are on the left side and parameters for the second instance are on the right side of the equation 
T1 - temperature in kelvin - 110 °C + 273 = 383 K
T2 - 65.0 °C + 273 = 338 K
substituting these values in the equation 

$\frac{22.5 psi}{383 K} = \frac{P}{338K}$
P = 19.9 psi 
new pressure is 19.9 psi