Question

A tire contains a mixture of gases with a total pressure of 245.0 torr. If the partial pressures of the oxygen, carbon dioxide, and nitrogen gases it contains are 51.3 torr, 0.10 torr, and 191.3 torr, respectively, what is the remaining partial pressure of the argon gas?

Answer 1

P_Total = 245.0 torr

P_O2 = 51.3 torr

P_CO2 = 0.10 tor

P_N2 = 191.3 torr

P_Ar = unknown

Solution:

Dalton's law of partial pressures states that the total pressure of a mixture of gases is equal to the sum of the partial pressures of the component gases.

Dalton's law can be expressed as:

P_Total ​= P_gas1 ​+ P_gas2 ​+ P_gas3 + ​... + P_gasN

Hence,

P_Total = P_O2 + P_CO2 + P_N2 + P_Ar

245.0 torr = 51.3 torr + 0.10 tor + 191.3 torr + P_Ar

245.0 torr = 242.7 + P_Ar

P_Ar = 2.3 torr

Answer: 2.3 torr is the remaining partial pressure of the argon (Ar) gas.