What Are Solutes That Don't Dissolve When Warmed?

Many gases are solutes whose solubility decreases with increasing temperature. For example, oxygen solubility in water increases as temperature decreases, enabling the existence of deep-sea aquatic life.

Carbonated beverages exemplify decreased gas solubility at elevated temperatures. A lukewarm soda goes flat much more quickly than a chilled soda because the carbon dioxide in the first has a lower solubility. The carbon dioxide molecules are attracted to one another while dissolved in the water at lower temperature. Increasing the thermal kinetic energy of the gas and water molecules of the system through heating enables more gas molecules to coalesce and form bubbles, which escape from the water because of their lower density.

Exceptions to this rule include molecular hydrogen, nitrogen and carbon monoxide in organic solvents such as carbon tetracholoride. The solubility of all three gases increases in these polar solvents with increasing temperature. The positive and negative correlations of solubility with temperature can both be attributed to the Le Chatelier principle, which states that systems under stress tend to relieve this stress and reach equilibrium. The addition of heat stresses solutions differently based on their interatomic and intermolecular forces. When equilibrium is favored through increasing solubility, this solubility increases with temperature.