Boyle's Law and Dalton's Law

This section explores two fundamental gas laws in chemistry: Boyle's Law and Dalton's Law of Partial Pressures.

Boyle's Law states that gas volume is inversely proportional to the pressure applied when temperature (T) and moles (n) are constant. The mathematical expression is P₁V₁ = P₂V₂.

Example: If 100 mL of oxygen under 150 kPa is put under a greater pressure of 200 kPa, the new volume will be 75.0 mL.

Dalton's Law of Partial Pressures states that the total pressure exerted by a mixture of gases is equal to the sum of the partial pressures of the component gases, assuming constant volume and temperature.

Formula: Pₜₒₜₐₗ = P₁ + P₂ + P₃ + ...

Example: In a mixture where Pₙ₂ = 79.10 kPa, Pₐᵣ = 0.040 kPa, and Pₒₜₕₑᵣₛ = 0.94 kPa, with a total pressure of 101.3 kPa, the partial pressure of oxygen (Pₒ₂) would be 21.2 kPa.

Highlight: When collecting gas bubbles through water, the pressure of water vapor must be included in calculations using Dalton's Law.

Gas Stoichiometry

This section applies gas laws and molar volume concepts to stoichiometric calculations in chemistry.

In gas stoichiometry, volume can be used similarly to moles in calculations.

Example:

1. In the reaction 2H₂ + O₂ → 2H₂O: If we start with 2 L of H₂, we will produce 2 L of H₂O and consume 1 L of O₂.

2. In the reaction 3KNO₃ + Ag₃PO₄ → 3AgNO₃ + K₃PO₄: If 3.4 mL of K₃PO₄ is produced, the reaction started with 10 mL of KNO₃.

These examples demonstrate how gas laws and stoichiometry can be combined to solve complex chemistry problems involving gases.