Gas Laws and Their Applications

Exam Reminder

• Check important email regarding upcoming exam after class.

Charles' Law

• Volume (V) is directly proportional to temperature (T) at constant moles and pressure.
• Formula: $\frac{V_1}{T_1} = \frac{V_2}{T_2}$
• Direct proportion: As one increases, the other increases.
• Convert temperature to Kelvin: $T(K) = T(°C) + 273.15$.
• Extrapolation of gas samples can show that they intersect at absolute zero (0 K or -273.15 °C).

Kinetic Theory Explanation

• Balloon in cold water contracts due to lower kinetic energy; in boiling water, it expands due to increased kinetic energy.
• Increased temperature leads to increased volume due to faster-moving gas particles.

Sample Problems

• Solve for final volume using Charles' Law under constant conditions, converting Celsius to Kelvin.

Avogadro's Law

• Volume (V) is directly proportional to moles of gas (n) at constant pressure and temperature.
• Formula: $\frac{V_1}{n_1} = \frac{V_2}{n_2}$
• Equal volumes of gas contain equal numbers of molecules at the same temperature and pressure.

Combined Gas Law

• Relates pressure (P), volume (V), temperature (T), and moles of gas in a single equation: $\frac{P_1V_1}{T_1} = \frac{P_2V_2}{T_2}$.
• Often used with moles constant.

Ideal Gas Law

• Formula: $PV = nRT$, where R is the gas constant.
• R values:
  • For atmosphere: $R = 0.08206 \frac{L \cdot atm}{mol \cdot K}$.
  • For mmHg: $R = 62.36 \frac{L \cdot mmHg}{mol \cdot K}$.
• This law allows calculation of one variable if the other three are known.

Next Steps

• Complete a gas law problem on page four of handout for review.
• Check email or Canvas for assignment updates and exam information.