Unit 7 Vocabulary: Phases and Thermochemistry

atm

An abbreviation for "atmosphere," a unit of pressure approximately equal to the average atmospheric pressure at sea level, used in measuring gas pressures.

Atmospheric Pressure

The force exerted by the air molecules in the Earth's atmosphere per unit area, typically measured in pascals or atmospheres.

Calorimetry

The science of measuring heat transfer from one object or process to another, often using a calorimeter.

Critical Point

The point in temperature and pressure on a phase diagram where the liquid and gaseous phases of a substance merge together into a single phase. Beyond the temperature of the critical point, the merged single phase is known as a supercritical fluid .

Deposition

The phase transition in which a gas transforms directly into a solid without passing through the liquid phase.

Heat

The transfer of thermal energy between systems due to a temperature difference.

Heat of Fusion

The amount of heat energy required to change a substance from a solid to a liquid at its melting point.

Heat of Vaporization

The amount of heat energy required to change a substance from a liquid to a gas at its boiling point.

Ideal Gas

A theoretical gas that perfectly follows the gas laws under all conditions of temperature and pressure.

Joule

The SI unit of energy, equivalent to one kilogram-meter squared per second squared.

Kelvin

The SI unit of temperature, used for gas law calculations, Equal to Celsius + 273.15

Kinetic Energy

The energy possessed by an object due to its motion.

Kinetic Molecular Theory

A theory explaining the behavior of gases based on the idea that they consist of small particles in constant motion with no attractions between molecules.

Phase

A distinct form or state of matter characterized by a set of physical properties, such as solid, liquid, or gas, and the forms between states of matter in which changes occur.

Phase Change

The transition of matter from one phase to another, such as from solid to liquid or liquid to gas.

Potential Energy

The stored energy of an object due to its position or condition, such as heat potential energy.

Pressure

The force exerted per unit area, typically measured in pascals or atmospheres.

Real Gas

A gas that does not strictly follow the assumptions of the ideal gas law under certain conditions.

Specific Heat

The amount of heat energy required to raise the temperature of a unit mass of a substance by one degree Celsius.

STP

The defined set of standard conditions for measuring gas volume, usually 0 degrees Celsius and 1 atmosphere of pressure.

Sublimation

The phase transition in which a substance transforms directly from a solid to a gas without passing through the liquid phase.

Temperature

A measure of the average kinetic energy of the particles in a substance.

Triple Point

The unique set of conditions at which the three phases (solid, liquid, and gas) of a substance coexist in equilibrium.

Vapor

The gaseous phase of a substance that is normally a liquid or solid at room temperature.

Vapor Pressure

The pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases at a given temperature in a closed system.