Key Concept 1.2 Phase Changes and Particle Interactions

Melting

• The process of changing from a solid to a liquid state.

• The process of changing from a liquid to a gas state.

• The process of changing from a gas to a solid state.

• The process of changing from a solid to a gas state.

Boiling (Vaporization)

• The process of a liquid turning into gas when heated to its boiling point.

• The slow evaporation of a liquid at any temperature.

• The condensation of vapor back into a liquid.

• The freezing of a liquid into a solid.

Deposition

• a physical process where a substance transitions directly from a gaseous state to a solid state without ever passing through the liquid phase

• a chemical reaction where a solid is formed from two liquids

• the process of a solid turning into a gas without becoming liquid first

• the process of a liquid turning into a solid through freezing

Temperature

• average kinetic energy of the particles in a substance.

• total energy of the particles in a substance.

• the amount of heat in a substance.

• the pressure exerted by the particles in a substance.

Heating Curve

• A graph that shows the change in temperature of a substance as heat is added, illustrating phase changes.

• A diagram that represents the molecular structure of a substance at different temperatures.

• A chart that displays the pressure changes of a gas during heating.

• A visual representation of the energy levels in an atom.

Heat Energy

• The energy stored in chemical bonds.

• The form of energy that is transferred between systems or objects with different temperatures (also known as thermal energy).

• The energy associated with the motion of particles in a substance.

• The energy released during nuclear reactions.

Endothermic Reaction

• A process that releases energy in the form of heat.

• A process that absorbs energy from its surroundings in the form of heat.

• A reaction that occurs spontaneously without energy input.

• A process that converts heat energy into chemical energy.

Exothermic Reaction

• A process that absorbs energy in the form of heat.

• A process or reaction that releases energy in the form of heat.

• A reaction that occurs only in the presence of a catalyst.

• A process that requires constant energy input to proceed.

Freezing

• The process of changing from a liquid to a solid state.

• The process of changing from a solid to a liquid state.

• The process of changing from a gas to a liquid state.

• The process of changing from a liquid to a gas state.

Temperature Change

• A variation in the degree of hotness or coldness measured by a thermometer, often resulting from heat energy transfer.

• A measure of the amount of heat energy in a substance.

• The process of converting heat energy into mechanical energy.

• A method of cooling substances to below their freezing point.