<u>Answer:</u> The number of moles of the gas is 1.31 mol.
<u>Explanation:</u>
To calculate the number of moles of gas, we use the equation given by ideal gas, which is:

where,
P = pressure of the gas = 203 kPa
V = volume of the gas = 20 L
n = Number of moles of gas = ? mol
R = Gas constant = 
T = temperature of the gas = 373 K
Putting values in above equation, we get:

Hence, the number of moles of the gas is 1.31 mol.