Assuming the gas behaves ideally, we can use the ideal gas law:
PV = nRT
where P is the pressure, V is the volume, n is the number of moles, R is the gas constant, and T is the temperature in Kelvin.
First, we need to convert the temperature from Celsius to Kelvin by adding 273.15:
T = 45°C + 273.15 = 318.15 K
Next, we can plug in the values we have and solve for pressure:
P = nRT/V
P = (2.2 mol)(0.08206 L·atm/mol·K)(318.15 K)/(7.5 L)
P ≈ 16.4 atm
Therefore, the pressure exerted by 2.2 moles of gas with a temperature of 45°C and a volume of 7.5 L is approximately 16.4 atm.