Solubility of a Gas in a Liquid
Factors influencing the maximum amount of gas that can dissolve in a given liquid at a specific temperature and pressure.
What is Solubility of a Gas in a Liquid?
The maximum amount of a gas that can dissolve in a given quantity of a liquid at a specific temperature and pressure to form a saturated solution.
Key formula / rule: Henry's Law
Key points
- Define the solubility of a gas in a liquid.
- Identify and explain the factors (nature of gas/liquid, temperature, pressure) that influence gas solubility.
- State and apply Henry's Law to calculate gas solubility or partial pressure.
- Explain the significance of Henry's Law constant (KH) and its relationship to solubility.
Common exam trap
Confusing the effect of temperature on gas solubility (decreases with increasing T) with solid solubility (usually increases with increasing T).
Definitions
- Term
Solubility of a Gas in a Liquid
- Meaning
The maximum amount of a gas that can dissolve in a given quantity of a liquid at a specific temperature and pressure to form a saturated solution.
- Term
Henry's Law
- Meaning
At a constant temperature, the solubility of a gas in a liquid is directly proportional to the partial pressure of the gas present above the surface of the liquid.
- Term
Henry's Law Constant (KH)
- Meaning
A proportionality constant in Henry's Law that is specific for a given gas-solvent pair at a particular temperature. A higher KH value indicates lower solubility of the gas.
Learning objectives
Define the solubility of a gas in a liquid.
Identify and explain the factors (nature of gas/liquid, temperature, pressure) that influence gas solubility.
State and apply Henry's Law to calculate gas solubility or partial pressure.
Explain the significance of Henry's Law constant (KH) and its relationship to solubility.
Relate the concept of gas solubility to real-world phenomena and applications.
Formulae
- Name
Henry's Law
- Note
P is the partial pressure of the gas above the solution, KH is Henry's Law constant, and x is the mole fraction of the gas in the solution. KH has units of pressure (e.g., bar, atm).
- Expression
P = KH * x
Prerequisites
Basic understanding of solutions (solute, solvent, solution).
Concept of mole fraction and partial pressure.
Le Chatelier's Principle.
Basic knowledge of intermolecular forces.
Common mistakes
Confusing the effect of temperature on gas solubility (decreases with increasing T) with solid solubility (usually increases with increasing T).
Incorrectly applying Henry's Law or misinterpreting the significance of KH (e.g., thinking higher KH means higher solubility).
Forgetting the limitations of Henry's Law, such as its applicability only for gases that do not react chemically with the solvent.
Not understanding that partial pressure, not total pressure, is relevant for Henry's Law when multiple gases are present.
Keywords
Solubility
Gas
Liquid
Henry's Law
Partial Pressure
Mole Fraction
Henry's Law Constant
Temperature Effect
Pressure Effect
Exothermic
Le Chatelier's Principle
Carbonated Drinks
The Bends
Anoxia
Practice preview
Which of the following statements is true regarding the effect of temperature on the solubility of a gas in a liquid?…
easy
According to Henry's Law, the partial pressure of the gas in vapor phase (p) is proportional to the mole fraction of the gas (x) in the solution. What is the mathematical representation of Henry's Law?…
easy
Which of the following gases would you expect to have the highest solubility in water at a given temperature and pressure?…
medium