NLN NEX Chemistry Practice Test

Solubility depends on both temperature and pressure because they change the balance of interactions that hold the solute and solvent together. When you raise the temperature, you’re supplying energy to break the solute’s lattice and form new interactions with the solvent. If the dissolution process is endothermic, heating makes it more favorable, so more solute dissolves. For many solids in liquids, solubility tends to increase with temperature, though there are exceptions when dissolution is exothermic. Pressure comes into play mainly for gases dissolving in liquids. According to Henry’s law, increasing the partial pressure of a gas above a solution pushes more gas into solution, so its solubility increases. For most solids, changing pressure has little effect on how much can dissolve. Agitation and surface area affect how fast dissolution occurs but not the total amount that can dissolve at equilibrium. So the true statement is that temperature and pressure do affect solubility.