3.4 Ideal Gas Law

Explain the relationship between the macroscopic properties of a sample of gas or mixture of gases using the ideal gas law.

• The macroscopic properties of ideal gases are related through the ideal gas law: EQN: PV = nRT.
• In a sample containing a mixture of ideal gases, the pressure exerted by each component (the partial pressure) is independent of the other components. Therefore, the partial pressure of a gas within the mixture is proportional to its mole fraction (X), and the total pressure of the sample is the sum of the partial pressures. EQN: PA = Ptotal × XA, where XA = moles A/total moles; EQN: Ptotal = PA + PB + PC + …
• Graphical representations of the relationships between P, V, T, and n are useful to describe gas behavior.