Chemistry Lecture Notes: Solutions

Comprehensive vocabulary flashcards covering basic concepts, concentration units, gas solubility, ideal and non-ideal behavior, colligative properties, and abnormal molecular masses from the Solutions chemistry chapter.

Solution

A homogeneous mixture of two or more substances in the same or different physical phases.

Binary Solution

A solution that consists of exactly two components.

Solvent

The component in a binary solution that is present in the larger quantity.

Solute

The component in a binary solution that is present in the smaller quantity.

Aqueous Solution

A solution in which water is used as the solvent.

Unsaturated Solution

A solution in which more solute can be dissolved without raising the temperature.

Saturated Solution

A solution in which no more solute can be dissolved further at a given temperature.

Supersaturated Solution

A solution that contains more solute than what would be necessary to saturate it at a given temperature.

Percentage by Weight ($\text{w/w }\%$)

The amount of solute present in $100\,\text{g}$ of solution, defined as $\text{w/w }\% = \frac{\text{weight of solute}}{\text{weight of solution}} \times 100$.

Percentage by Volume ($\text{v/V }\%$)

The volume of solute present in $100\,\text{mL}$ of solution, defined as $\text{v/V }\% = \frac{\text{volume of solute}}{\text{volume of solution}} \times 100$.

Percentage of Mass by Volume ($\text{w/V }\%$)

The weight of solute present in $100\,\text{mL}$ of solution, defined as $\text{w/V }\% = \frac{\text{weight of solute}}{\text{volume of solution}} \times 100$.

Mole Fraction ($\chi$)

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

Parts Per Million (ppm)

The parts of a component per million parts ($10^6$) of the solution, widely used when a solute is present in trace quantities.

Molarity ($M$)

The number of moles of solute present in $1\,\text{L}$ ($1\,\text{dm}^3$) of the solution. It varies with temperature due to volume changes.

Molality ($m$)

The number of moles of solute per kilogram of the solvent. It is independent of temperature.

Normality ($N$)

The number of gram equivalents of solute present in $1\,\text{L}$ of solution.

Formality ($F$)

The number of formula weights of solute present per litre of the solution.

Demal ($D$)

A concentration unit representing one mole of solute present in $1\,\text{L}$ of solution at $0\,^\circ\text{C}$.

Henry's Law

States that the partial pressure ($p$) of a gas in the vapour phase is proportional to the mole fraction ($x$) of the gas in the solution ($p = K_H x$).

Henry's Law Graph

A linear plot showing partial pressure of solute on the y-axis against mole fraction of component in its solution on the x-axis.

Anoxia

A condition experienced by climbers at high altitudes where low atmospheric partial pressure of $\text{O}_2$ leads to low concentrations of oxygen in the blood.

Vapour Pressure

The pressure exerted by vapour molecules above the liquid surface in equilibrium with the liquid at a given temperature.

Raoult's Law

States that for a solution of two volatile liquids, the partial vapour pressure of each liquid is directly proportional to its mole fraction in solution ($p_A = p_A^\circ \chi_A$).

Ideal Solution

A solution in which solute-solute ($\text{B--B}$) and solvent-solvent ($\text{A--A}$) interactions are almost similar to solvent-solute ($\text{A--B}$) interactions, obeying Raoult's law with $\Delta H = 0$ and $\Delta V = 0$.

Non-Ideal Solution Showing Positive Deviation

A solution where $\text{A--B}$ interactions are weaker than $\text{A--A}$ or $\text{B--B}$ interactions, resulting in higher vapour pressure than predicted by Raoult's law, $\Delta H > 0$, and $\Delta V > 0$.

Non-Ideal Solution Showing Negative Deviation

A solution where $\text{A--B}$ interactions are stronger than $\text{A--A}$ or $\text{B--B}$ interactions, leading to lower vapour pressure than predicted by Raoult's law, $\Delta H < 0$, and $\Delta V < 0$.

Azeotropic Mixture

A mixture of two liquids that boils at a specific temperature like a pure liquid and distils over in the exact same composition.

Minimum Boiling Azeotropes

Constant boiling mixtures formed by liquid pairs showing positive deviation from ideal behavior, having boiling points lower than either component.

Maximum Boiling Azeotropes

Constant boiling mixtures formed by liquid pairs showing negative deviation from ideal behavior, having boiling points higher than either component.

Colligative Properties

Properties of solutions that depend solely on the number of solute particles present, regardless of their chemical nature.

Relative Lowering of Vapour Pressure

The ratio of the lowering in vapour pressure to the vapour pressure of the pure solvent, which equals the mole fraction of the solute.

Ebullioscopic Constant ($K_b$)

The molal elevation constant representing the change in boiling point produced by a $1\,\text{m}$ solution, expressed in units of $\text{K\,kg\,mol}^{-1}$.

Elevation in Boiling Point Graph

A plot showing how the vapour pressure curves of a pure solvent and a solution shift relative to atmospheric pressure ($1\,\text{atm}$), leading to a higher boiling point $T_b$.

Cryoscopic Constant ($K_f$)

The molal depression constant representing the decrease in freezing point produced by a $1\,\text{m}$ solution, expressed in units of $\text{K\,kg\,mol}^{-1}$.

Depression in Freezing Point Graph

A diagram showing vapour pressure versus temperature where the solution curve intersects the frozen solvent curve at a lower temperature $T_f$ than the pure solvent $T_f^\circ$.

Osmosis

The spontaneous movement of solvent molecules through a semipermeable membrane from a region of pure solvent or dilute solution to a more concentrated solution.

Osmotic Pressure ($\pi$)

The hydrostatic pressure applied to a solution that just prevents the inflow of pure solvent through a semipermeable membrane, given by $\pi = RCT$.

Hypertonic Solution

A solution that possesses a higher osmotic pressure compared to another solution across a semipermeable membrane.

Hypotonic Solution

A solution that possesses a lower osmotic pressure compared to another solution across a semipermeable membrane.

Isotonic Solution

Two solutions that exert the same osmotic pressure and share identical molar concentrations.

Plasmolysis

The phenomenon in which fluid leaves a plant cell causing it to shrink when placed in a hypertonic solution.

Reverse Osmosis

The flow of solvent from a solution to pure solvent occurring when external pressure exceeding osmotic pressure is applied to the solution.

van 't Hoff Factor ($i$)

The ratio of the observed value of a colligative property to its calculated theoretical value, used to account for particle dissociation or association.

Degree of Dissociation ($\alpha$)

The fraction of solute molecules that separate into individual ions in solution, expressed as $\alpha = \frac{i - 1}{n - 1}$.

Degree of Association ($\alpha$)

The fraction of solute molecules that combine together in solution, expressed as $\alpha = \frac{1 - i}{1 - \frac{1}{n}}$.