Gases, Aqueous Solutions, and Acid-Base Chemistry

Comprehensive vocabulary flashcards covering the properties and laws of gases, the unique physical and chemical characteristics of water, aqueous solutions, colloids, and acid-base buffer systems.

Kinetic Theory of Gases

A theoretical model stating that gas particles move randomly and rapidly, have large spaces between them, exert pressure upon colliding with container walls, undergo elastic collisions, and experience no attractive forces toward one another.

Gas Pressure ($P$)

The force ($F$) exerted per unit area ($A$) when gas particles collide with a surface: $\text{Pressure} = \frac{F}{A}$.

Atmospheric Pressure

The total pressure exerted on the surface of the Earth by the combined mixture of all gases present in the atmosphere.

Pressure Unit Equivalencies

The standard relationships between different pressure units: $1\,\text{atm} = 760.\,\text{mm\,Hg} = 760.\,\text{torr} = 14.7\,\text{psi} = 101{,}325\,\text{Pa}$.

Ideal Gas

A hypothetical gas that behaves exactly according to all the assumptions of the kinetic molecular theory under all conditions.

Ideal Gas Law

The equation combining all four gas properties for an ideal gas: $PV = nRT$, where $P$ is pressure, $V$ is volume, $n$ is moles, $R$ is the universal gas constant, and $T$ is temperature in Kelvin.

Universal Gas Constant ($R$)

The proportionality constant in the Ideal Gas Law, equal to $0.0821\,\text{L}\cdot\text{atm}/(\text{mol}\cdot\text{K})$ or $62.4\,\text{L}\cdot\text{mm\,Hg}/(\text{mol}\cdot\text{K})$.

Boyle’s Gas Law

A gas law stating that for a fixed amount of gas at constant temperature, pressure and volume are inversely related ($P_1V_1 = P_2V_2$ or $PV = k$).

Charles’s Gas Law

A gas law stating that for a fixed amount of gas at constant pressure, volume is directly proportional to its Kelvin temperature ($\frac{V_1}{T_1} = \frac{V_2}{T_2}$ or $\frac{V}{T} = k$).

Gay-Lussac’s Gas Law

A gas law stating that for a fixed amount of gas at constant volume, pressure is directly proportional to its Kelvin temperature ($\frac{P_1}{T_1} = \frac{P_2}{T_2}$ or $\frac{P}{T} = k$).

Combined Gas Law

An equation that combines Boyle's, Charles's, and Gay-Lussac's laws into one relationship ($\frac{P_1V_1}{T_1} = \frac{P_2V_2}{T_2}$) to evaluate changes among pressure, volume, and temperature simultaneously.

Avogadro’s Gas Law

A gas law stating that at constant temperature and pressure, the volume of a gas is directly proportional to the number of moles of gas present ($\frac{V_1}{n_1} = \frac{V_2}{n_2}$ or $\frac{V}{n} = k$).

Standard Temperature and Pressure (STP)

A standardized set of conditions defined as $1\,\text{atm}$ and $273\,\text{K}$, under which $1\,\text{mol}$ of an ideal gas occupies exactly $22.4\,\text{L}$ ($6.02 \times 10^{23}\,\text{particles}$).

Ozone ($\text{O}_3$)

A gas located in the upper atmosphere (stratosphere) that shields the Earth by absorbing high-energy ultraviolet (UV) radiation, which is degraded by chlorofluorocarbons (CFCs).

Hydrogen Bond

An intermolecular attraction formed when a hydrogen atom covalently bonded to an electronegative atom (such as oxygen or nitrogen) is simultaneously attracted to another electronegative atom.

Cohesion

The property by which water molecules remain linked to one another via multiple hydrogen bonds, assisting in the transport of water against gravity in plants.

Adhesion

The clinging of one substance to an entirely different substance, such as water molecules binding to the walls of water-conducting plant cells.

Surface Tension

A measure of how difficult it is to stretch or break the surface of a liquid, produced in water by extensive intermolecular hydrogen bonding.

Thermal Energy

A measure of the total amount of kinetic energy within a substance resulting from the motion of its molecules.

Temperature

A physical measurement representing the average kinetic energy of the molecules in a body of matter.

Heat

Thermal energy in the process of transferring from one body of matter to another.

Water's High Specific Heat

The ability of water to absorb or release large amounts of heat with minimal change in its own temperature, caused by hydrogen bonds absorbing heat when breaking and releasing heat when forming.

Heat of Vaporization

The quantity of heat that must be absorbed for $1\,\text{g}$ of a liquid to be transformed into the gaseous state.

Evaporative Cooling

The decrease in temperature of a liquid's remaining surface as high-kinetic-energy molecules escape into the vapor phase, which helps stabilize temperatures in organisms and bodies of water.

Hydration Shell

A sphere of oriented water molecules that surrounds and isolates each individual ion when an ionic solid dissolves in aqueous solution.

Hydrophilic

Property characterizing a polar or ionic substance that exhibits an affinity for and dissolves readily in water.

Hydrophobic

Property characterizing a substance that lacks an affinity for water, typically consisting of nonpolar covalent molecules such as oils.

Henry’s Law

A principle stating that the solubility of a gas dissolved in a liquid is directly proportional to the partial pressure of that gas above the liquid.

Saturated Solution

A solution that contains the exact maximum amount of dissolved solute that can dissolve in a specific quantity of solvent at a designated temperature.

Supersaturated Solution

An unstable solution that temporarily contains more than the maximum equilibrium amount of dissolved solute possible at a given temperature.

Electrolyte

A compound that dissociates into ions when dissolved in water, producing a solution that conducts an electric current.

Nonelectrolyte

A substance that dissolves in water yielding neutral intact molecules without forming ions, producing a solution that does not conduct electricity.

Dissociation

The separation of cations and anions that takes place when an ionic solid dissolves in water to form an aqueous solution.

Strong Electrolyte

A solute that dissociates completely or nearly completely into ions in aqueous solution (e.g., $\text{NaCl}$).

Weak Electrolyte

A solute that only partially dissociates into ions in aqueous solution, leaving the majority of dissolved solute molecules intact.

Colloid

A heterogeneous mixture in which dispersed particles range between $1\text{--}1000\,\text{nm}$ in diameter, do not separate upon standing, and pass through standard filters.

Suspension

A heterogeneous mixture containing particles larger than $1000\,\text{nm}$ in diameter that settle out upon standing and can be separated by filtration.

Tyndall Effect

The scattering of visible light caused by dispersed particles in a colloid or fine suspension, distinguishing them from true homogeneous solutions.

Emulsion

A colloidal dispersion of microdroplets of one liquid dispersed uniformly throughout another immiscible liquid or a solid (e.g., butter, mayonnaise).

Brønsted-Lowry Acid

A substance that acts as a proton ($\text{H}^+$) donor, contains hydrogen in its formula, and produces hydronium ($\text{H}_3\text{O}^+$) in water.

Brønsted-Lowry Base

A substance that acts as a proton ($\text{H}^+$) acceptor, which must possess a lone pair of electrons available to coordinate with a proton.

Conjugate Base

The chemical species that remains after a Brønsted-Lowry acid has donated a proton ($\text{H}^+$).

Conjugate Acid

The chemical species formed when a Brønsted-Lowry base accepts a proton ($\text{H}^+$).

Buffer Solution

A solution containing approximately equal concentrations of a weak acid and the salt of its conjugate base that resists significant changes in pH upon addition of small amounts of acid or base.

Carbonic Acid-Bicarbonate Buffer

The primary physiological buffer system in blood ($\text{CO}_2(g) + \text{H}_2\text{O}(l) \rightleftharpoons \text{H}_2\text{CO}_3(aq) \rightleftharpoons \text{H}_3\text{O}^+(aq) + \text{HCO}_3^-(aq)$) that maintains arterial blood pH within the vital range of $7.35\text{--}7.45$.