Question

When the pressure that a gas exerts on a sealed container changes from 1100 bar to 75.5 bar, the temperature changes from k to 298 k?

Answer 1

Gay-Lussac's law gives the relationship between pressure and temperature of gas. For a fixed amount of gas, pressure is directly proportional to temperature at constant volume.
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 
substituting the values in the equation 
$\frac{1100 bar}{T} = \frac{75.5 bar}{298 K}$
T = 4342 K
initial temperature was 4342 K