Gases, Liquids, and Solids

Comprehensive vocabulary flashcards covering the physical states of matter, gas laws, intermolecular forces, and phase transitions from Chapter 5 lecture notes.

Avogadro's Law

A principle stating that equal volumes of gases at the same temperature and pressure contain the same number of molecules.

Standard Temperature and Pressure (STP)

Standard conditions defined as $1.00\,\text{atm}$ ($760\,\text{mm Hg}$) and $0^\circ\text{C}$ ($273\,\text{K}$, where $1\,\text{mol}$ of any gas occupies $22.4\,\text{L}$ and contains $6.02 \times 10^{23}$ molecules.

Ideal Gas Law

The relationship valid for any quantity of gas ($n$) relating pressure ($P$), volume ($V$), and temperature ($T$), expressed as $PV = nRT$.

Ideal Gas Constant ($R$)

A universal constant for all gases equal to $0.0821\,\text{L}\cdot\text{atm}\cdot\text{mol}^{-1}\cdot\text{K}^{-1}$.

Intermolecular Attractive Forces (IMAF)

Forces between particles that counteract kinetic energy and help determine whether a substance is a solid, liquid, or gas at any given temperature.

Gaseous State

A state of matter characterized by high temperature and high kinetic energy, where particles move so fast that intermolecular attractive forces are too weak to hold them together; has no definite shape and takes the volume of its container.

Liquid State

A state of matter characterized by lower temperatures where particles move slowly enough for a gas to condense; has a definite volume but no definite shape.

Solid State

A state of matter characterized by very slow particle movement at low temperatures without enough energy to move past each other; has both a definite shape and a definite volume.

Melting Point

The temperature at which a solid is heated and transitions into a liquid.

Surface Tension

A layer on the surface of a liquid produced by the strength of intermolecular attractions between molecules at the surface layer.

Vapor Pressure

The pressure exerted by a gas in equilibrium with its liquid form inside a closed container.

Relative Humidity

The ratio of the actual partial pressure of water vapor in air to the equilibrium vapor pressure of water at the relevant temperature, expressed as $\text{RH} = \frac{P_{\text{H}_2\text{O}}}{P^\circ_{\text{H}_2\text{O}}} \times 100\%$.

Boiling Point

The temperature at which the vapor pressure of a liquid is equal to the pressure of the atmosphere in contact with its surface.

Normal Boiling Point

The boiling point of a liquid at an atmospheric pressure of $1\,\text{atm}$ (for example, $100^\circ\text{C}$ for water).

Dalton's Law of Partial Pressures

A law stating that the total pressure of a mixture of gases is equal to the sum of the partial pressures of each individual gas in the mixture ($P = P_1 + P_2 + P_3 + \dots$).

Partial Pressure

The pressure that an individual gas within a mixture of gases would exert if it were alone in the container.

Kinetic Molecular Theory

A theory describing the relationship between the observed macroscopic behavior of gases and the microscopic behavior and collisions of individual molecules based on 6 assumptions.

Ideal Gas

A hypothetical gas whose behavior is completely described by the 6 assumptions of the Kinetic Molecular Theory.

Solidification

The phase change or transition from a liquid to a solid.

London Dispersion Force

A weak intermolecular attraction between atoms or molecules resulting from electrostatic attraction between temporary, induced dipoles.

Temporary Dipole

A brief moment lasting only a tiny fraction of time when electron density shifts more toward one part of an atom than another, inducing complementary attractive dipoles in neighboring atoms.

Dipole-Dipole Interaction

The attractive force between the positive end of one dipole and the negative end of another dipole, existing in both identical and different polar molecules.

Hydrogen Bonding

A strong noncovalent force of attraction between a partial positive charge on a hydrogen atom bonded to a highly electronegative atom ($\text{O}$, $\text{N}$) and a partial negative charge on a nearby oxygen or nitrogen atom.

Crystallization

The process of forming a solid from a liquid where atoms, molecules, or ions adopt an orderly arrangement.

Amorphous Solid

A solid whose atoms, molecules, or ions are not arranged in an orderly fashion; characterized as soft, able to flow, and lacking a distinct melting point.

Allotropes

Different structural forms of the same element in the same physical state that possess different physical and chemical properties.

Heat of Fusion

The quantity of heat or energy necessary to melt a given amount of a solid.

Sublimation

The phase transition in which a substance changes directly from the solid state to the vapor state without passing through the liquid state.

Pressure

The force per unit area exerted against a surface.

Barometer

A device used to measure atmospheric pressure, commonly expressed in millimeters of mercury ($\text{mm Hg}$).

Manometer

An instrument used to measure the pressure of a gas inside a container.

Boyle's Law

A gas law stating that for a fixed mass of ideal gas at constant temperature, the volume is inversely proportional to the applied pressure ($PV = \text{constant}$, or $P_1 V_1 = P_2 V_2$).

Charles's Law

A gas law stating that the volume of a fixed mass of ideal gas at constant pressure is directly proportional to its temperature in Kelvins ($\frac{V}{T} = \text{constant}$, or $\frac{V_1}{T_1} = \frac{V_2}{T_2}$).

Gay-Lussac's Law

A gas law stating that for a fixed mass of gas at constant volume, the pressure is directly proportional to temperature in Kelvins ($\frac{P}{T} = \text{constant}$, or $\frac{P_1}{T_1} = \frac{P_2}{T_2}$).

Combined Gas Law

A gas law combining Boyle's, Charles's, and Gay-Lussac's laws for a fixed mass of gas, expressed as $\frac{PV}{T} = \text{constant}$ or $\frac{P_1 V_1}{T_1} = \frac{P_2 V_2}{T_2}$.