(455) Ideal gas law equations [IB Physics SL/HL]

Ideal Gas Law

• Equation: PV = nRT

  • P = Pressure (Pa)

  • V = Volume (m³)

  • n = Number of moles

  • R = Ideal gas constant (8.31 J/(mol·K))

  • T = Temperature (K)

Importance of Empirical Experiments

• Gas laws developed from experiments before known constants.

• Proportionality observed in the ratios of P * V / T.

Key Scenarios in Gas Law

Constant Volume (Isocoric)

• If V is constant, P is proportional to T.

• Graph: Pressure (P) vs. Temperature (T) is linear, passing through origin.

• As T increases, P increases (direct relationship).

Constant Pressure

• If P is constant, V is proportional to T.

• Graph: Volume (V) vs. Temperature (T) is linear.

• As T increases, V increases (direct relationship).

Constant Temperature (Isothermal)

• If T is constant, P is proportional to 1/V.

• Graph: Pressure (P) vs. Volume (V) is hyperbolic.

• As V increases, P decreases (inverse relationship).

Additional Insights

• Real-life applications:

  • Explains balloon expansion at high altitudes.

  • Military example of pressure effects in high altitude training.

  • Importance of understanding pressure and volume relationships in aviation.

Conclusion

• Understanding of the ideal gas law is crucial for real-life applications and scientific investigations into gas behavior.