Henry's Law

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Interactive Henry's Law Demonstration

Explore how changing pressure and temperature affects the solubility of different gases in water. Use the controls to adjust parameters and observe the molecular behavior according to Henry's Law.

Select Gas:
Pressure: 1.0 atmHigher pressure = More gas dissolved
Temperature: 298 K (24.9°C)Higher temperature = Less gas dissolved
Oxygen (O₂) (P = 1.0 atm)Dissolved Oxygen (O₂)Concentration = 0.0013 mol/LC = kH × P

Henry's Law

Henry's Law states that at a constant temperature, the amount of a gas that dissolves in a liquid is directly proportional to the partial pressure of that gas in equilibrium with the liquid.

Mathematically: C = kH × P

Where:

  • C = concentration of dissolved gas (mol/L)
  • kH = Henry's constant (mol/(L·atm))
  • P = partial pressure of the gas (atm)

Henry's constant depends on:

  • The nature of the gas
  • The nature of the solvent
  • Temperature (solubility decreases as temperature increases)

Real-world example: Carbonated beverages contain more dissolved CO₂ under pressure. When you open the bottle (reducing pressure), the gas escapes as bubbles.

Click on the animation to pause

Applications of Henry's Law

  • 1

    Carbonated Beverages

    Soda and beer are bottled under pressure to increase CO₂ solubility. When opened, pressure decreases and gas escapes as bubbles.

  • 2

    Deep-Sea Diving

    At high pressures underwater, more nitrogen dissolves in blood. Ascending too quickly can cause decompression sickness as gas forms bubbles in tissues.

Henry's Law Limitations

  • 1

    Chemical Reactions

    Henry's Law doesn't apply when the gas reacts with the solvent. For example, HCl gas dissolving in water forms ions, not molecular HCl.

  • 2

    High Pressure Conditions

    The law becomes less accurate at very high pressures where gas behavior deviates from ideality.

Sample Problem

The solubility of oxygen in water at 298 K is 1.2 × 10-3 mol/L when the partial pressure of oxygen is 1 atm. Calculate the concentration of dissolved oxygen when the partial pressure is increased to 2.5 atm (assuming the same temperature).

Solution:

According to Henry's Law: C = kH × P

At P1 = 1 atm, C1 = 1.2 × 10-3 mol/L

Therefore, kH = C1/P1 = 1.2 × 10-3 mol/(L·atm)

At P2 = 2.5 atm:

C2 = kH × P2 = 1.2 × 10-3 mol/(L·atm) × 2.5 atm

C2 = 3.0 × 10-3 mol/L