To solve this question, you need to use Clapeyron's equation:
P.V = n.R.T
P = pressure generated by the gas on the walls of the container;
V = volume occupied by the gas and can be expressed in liters or cubic meters;
n = number of mol (amount of substance in the gas);
R = general gas constant proposed by Clapeyron and depends on the pressure unit used (in atm, it is 0.082; in mmHg, it is 62.3; in KPa, it is 8.31);
T = temperature at which the gas is subjected (always used in the unit Kelvin).
So we have:
n = 1.13
P = 2.6 atm
V = 18.4 L
T = ?
R = 0.082 atm.L/mol.K
PV = nRT
2.6 x 18.4 = 1.13 x 0.082 x T
47.84 = 0.09266T
T = 516.3 K
Answer: The temperature is 516.3 K