Lesson 4

Gas Laws Overview

• Boyle's Law: At constant temperature, volume and pressure are inversely proportional.

  • Application: Pneumatic bellows and diaphragm contraction.

• Charles' Law: At constant pressure, temperature and volume are directly proportional.

  • Application: LMA cuff ruptures in an autoclave.

• Gay-Lussac's Law: At constant volume, temperature and pressure are directly proportional.

  • Application: Oxygen tank explosions in heat.

• Ideal Gas Law: Unifies gas laws into one equation: $PV = nRT$.

  • Simplified form: $P = \frac{T}{V}$.

Key Relationships Between Variables

• Boyle's Law: $P_1 V_1 = P_2 V_2$

  • Inverse relationship: As one variable increases, the other decreases.

• Charles' Law: $\frac{V_1}{T_1} = \frac{V_2}{T_2}$

  • Direct relationship: Both variables increase or decrease together.

• Gay-Lussac's Law: $\frac{P_1}{T_1} = \frac{P_2}{T_2}$

  • Direct relationship: Both variables increase or decrease together.

Mnemonic for Gas Laws

• "Paid TV Can Be Great":

  • Top row: Pressure, Temperature, Volume (P, T, V).
  • Bottom row: Gas Laws (Charles, Boyle, Gay-Lussac).

• Red variable is constant; blue variables are variable in the law.

Practical Examples of Gas Laws

• Boyle's Law Examples:

  • Diaphragm contraction, pneumatic bellows, bag valve mask, bourdon gauge for O2 cylinder.

• Charles' Law Example:

  • LMA cuff ruptures in autoclave.

• Gay-Lussac's Law Example:

  • Oxygen tank explosion in heat.

• Ideal Gas Law Components:

  • $P$: Pressure, $V$: Volume, $n$: Moles, $r$: 0.0821 $ext{L atm K}^{-1} ext{mol}^{-1}$, $T$: Temperature.