CHEM 162: General Chemistry II - Chapter 13: Solutions

Vocabulary flashcards derived from the CHEM 162 lecture on Solutions, covering definitions, energetics of formation, solubility laws, and concentration units.

Solution

A homogeneous mixture of 2 or more substances.

Solute

The substance being dissolved, typically present in the lesser amount.

Solvent

The substance doing the dissolving, typically present in the greater amount.

Aqueous solution

A solution in which water acts as the solvent.

Entropy

A measure of energy randomization or energy dispersal in a system, representing disorder or the tendency for energy to spread out.

Exothermic

A process where energy is released and the change in enthalpy $\Delta H$ is negative ($-$).

Endothermic

A process where energy is absorbed and the change in enthalpy $\Delta H$ is positive ($+$).

Hydrogen bond

A special dipole-dipole intermolecular force occurring when a hydrogen atom bonded to $O$, $N$, or $F$ is electrostatically attracted to a lone pair of electrons on an $O$, $N$, or $F$ atom in another molecule.

Complementary base pairs

Specific nitrogenous base pairings in DNA, specifically adenine and thymine ($AT$) or guanine and cytosine ($GC$), which maximize hydrogen bonding.

Enthalpy of solution ($\Delta H_{solution}$)

Given by the equation $\Delta H_{solution} = \Delta H_{solute} + \Delta H_{solvent} + \Delta H_{mix}$, representing the total energy change when a solution forms.

Heat of hydration ($\Delta H_{hydration}$)

The heat emitted when $1\,mol$ of a gaseous solute ion dissolves in water, equal to the sum of $\Delta H_{solvent}$ and $\Delta H_{mix}$.

Dynamic Equilibrium

The state where the rate of dissolution equals the rate of recrystallization.

Saturated solution

A solution containing the maximum amount of dissolved solute possible at a specific temperature and pressure, in dynamic equilibrium with undissolved solute.

Unsaturated solution

A solution containing less than the maximum amount of solute that can be dissolved under specific temperature and pressure conditions.

Supersaturated solution

An unstable solution that contains more than the maximum amount of solute possible for a saturated solution at a given temperature and pressure.

Henry’s Law

States that the solubility of a gas ($S_{gas}$) in a liquid is directly proportional to the partial pressure of the gas over the liquid ($P_{gas}$), expressed as $S_{gas} = k_H P_{gas}$.

Molarity ($M$)

A unit of concentration defined as the $\text{moles of solute}$ per $1\,L$ of solution.

Molality ($m$)

A unit of concentration defined as the $\text{moles of solute}$ per $1\,kg$ of solvent.

Mole fraction ($\chi_a$)

The ratio of the moles of one component to the total moles of all components in the solution.

Mole percentage (mol %)

The result of the mole fraction ($\chi_a$) multiplied by $100\%$.

Brass

A solution of zinc in copper.

Bronze

A solution of tin in copper.