Chapter 7: Gases, Liquids, Solids, and Attractive Forces

Vocabulary flashcards covering the kinetic molecular theory, gas laws, phase changes, attractive intermolecular forces, and solubility concepts from Chapter 7.

Pressure

A force exerted against a given area, describing how hard something pushes against something else.

Millimeters of Mercury ($\text{mmHg}$)

A unit of pressure commonly used to measure blood pressure, where $760\,\text{mmHg}$ is equal to $1\,\text{atm}$ at sea level.

Atmospheric Pressure at Sea Level

Standard environmental pressure measured as $1\,\text{atm}$, $760\,\text{mmHg}$, $14.7\,\text{psi}$, or $101{,}325\,\text{Pa}$.

Mercury Barometer

An instrument that measures atmospheric pressure, where at sea level the mercury column is approximately 760 high ($760\,\text{mmHg} = 1\,\text{atm}$).

Kinetic Molecular Theory of Gases

A theory explaining how gas particles move and behave, based on the concepts of movement ('kinetic'), molecules ('molecular'), and explanations ('theory').

Ideal Gas

A theoretical model of a gas that follows all the rules and assumptions of the kinetic molecular theory perfectly.

Boyle's Law

A gas law stating that pressure and volume are inversely related; increasing pressure decreases volume, represented by the formula $P_1V_1 = P_2V_2$.

Charles's Law

A gas law stating that when pressure is constant, temperature and volume increase or decrease together, represented by the formula $\frac{V_1}{T_1} = \frac{V_2}{T_2}$ using Kelvin ($K = {}^\circ\text{C} + 273$).

Gay-Lussac's Law

A gas law stating that temperature and pressure move together; heating a gas increases its pressure, represented by the formula $\frac{P_1}{T_1} = \frac{P_2}{T_2}$ in Kelvin.

Combined Gas Law

A gas law formula used when pressure, volume, and temperature can all change simultaneously: $\frac{P_1V_1}{T_1} = \frac{P_2V_2}{T_2}$.

Ideal Gas Law

The equation of state $PV = nRT$, where $P$ is pressure, $V$ is volume, $n$ is the number of moles, $R$ is the ideal gas constant, and $T$ is temperature in Kelvin.

Melting

A change of state from a solid to a liquid.

Freezing

A change of state from a liquid to a solid.

Evaporation

A change of state from a liquid to a gas.

Condensation

A change of state from a gas to a liquid.

Sublimation

A change of state directly from a solid to a gas.

Deposition

A change of state directly from a gas to a solid.

Vapor Pressure

The pressure created by vapor above a liquid in a closed container when a physical equilibrium is reached between evaporation and condensation.

Boiling Point

The temperature at which the vapor pressure of a liquid equals the atmospheric pressure.

London Forces

The weakest attractive forces, caused by temporary uneven movements of electrons that induce temporary attractions; present in all molecules and significant in nonpolar molecules.

Dipole-Dipole Attraction

An attractive force occurring between polar molecules that have permanent, oppositely charged positive and negative ends.

Hydrogen Bonding

A stronger type of dipole-dipole attraction occurring when hydrogen is attached to $\text{O}$, $\text{N}$, or $\text{F}$ and attracts a lone pair on another $\text{O}$, $\text{N}$, or $\text{F}$.

Ion-Dipole Attraction

An attractive force occurring between an ion and a polar molecule, such as the negative oxygen end of water attracting $\text{Na}^+$ and the positive hydrogen end attracting $\text{Cl}^-$.

Ion Attraction

The strongest attractive force, which occurs when oppositely charged ions attract each other (e.g., positive sodium and negative chloride).

Melting Point

The temperature at which a solid turns into a liquid; increases with stronger and more numerous attractive forces.

Solubility

The amount of a substance that can dissolve in a specific quantity of another substance at a particular temperature, operating under the principle of 'like dissolves like'.

Hydrophilic

A term describing 'water loving' substances that interact favorably with and dissolve in water.

Hydrophobic

A term describing 'water hating' substances that do not mix well with water.

Hydration

The process by which polar water molecules surround and stabilize ions when an ionic compound dissolves in water.

Amphipathic Compounds

Molecules that contain both a polar (water-loving) region and a nonpolar (water-avoiding) region, such as fatty acids.

Micelles

Tiny spherical arrangements of soap molecules where the water-loving heads face outward toward water and the water-hating portions face inward.

Emulsifier

A substance that helps oil and water remain mixed together in a mixture.