Answer to Question #337066 in General Chemistry for cutie

Question

A mixture of 50.0 g of nitrogen and 35.0 g of oxygen has a total pressure of 0.900 atm. What is the partial pressure of each gas?

Answer 1

P_i = χ_i × P_total

P_i  - the partial pressure of component i

χ_i - its mole fraction in the mixture

P_total - the total pressure of the mixture

n(N₂) = m(N₂) / Mr(N₂) = 50.0 g / 28 g/mol = 1.79 moles

n(O₂) = m(O₂) / Mr(O₂) = 35 g / 32 g/mol = 1.09 moles

n_total = n(N₂) + n(O₂) = 1.79 moles + 1.09 moles = 2.88 moles

χ_i = number of moles of i / total number of moles

P(N₂) = (1.79 mol / 2.88 mol) * 0.900 atm = 0.559 atm

P(O₂) = (1.09 mol / 2.88 mol) * 0.900 atm = 0.341 atm