Equivalent conversions:
1 atm = 760 mm Hg = 101.325 kPa
Dalton’s law is presented in this formula, P = p1 + p2 + … +pn where p1, p2 to pn are the pressures of the individual gases and the P is the total pressure.
Let p1 = CO2, p2 = O2 and p3 = N2
p1 = 125mmHg (1 atm/760 mmHg) = 0.1645 atm
p2 = 22 kPa (1 atm/101.325 mmHg) = 0.2171 atm
P = p1 + p2 + p3
1.5atm = 0.1645 atm + 0.2171 atm + p3
p3 = N2 = 1.1184 atm