One mol of air contains 0.74 moles of nitrogen gas and 0.25 mol of oxygen gas. Compute the partial pressure of these gases at a total pressure of 1.7 atm and at a total pressure of 4.7 atm.

Explanation:

Partial pressure of a gas is the product of the mole fraction of that gas, which is the ratio of the no. of moles of the gas to the total no. of moles, and the total pressure.

total no. of moles=0.74+0.25=0.99 mol

mole fraction of N2=0.74/0.99=0.7475

mole fraction of O2=0.25/0.99=0.2525

total pressure=1.7+4.7=6.4 atm

partial pressure of N2=0.7475×6.4=4.784 atm

partial pressure of O2=0.2525×6.4=1.616 atm