Transformation of Matter: Energy in Physical and Chemical Reactions

This collection of flashcards covers key concepts and vocabulary related to the transformation of matter, energy changes in chemical reactions, and thermodynamic principles.

Thermodynamics

The study of energy and its interconversions.

Kinetic Energy

The energy an object possesses by virtue of its motion.

Potential Energy

A retrievable form of energy that depends on an object's position or composition.

First Law of Thermodynamics

Energy cannot be created nor destroyed, only transformed.

Internal Energy

The sum of the kinetic and potential energies of all the particles in a system.

State Function

A property that depends only on the current state of the system, not on the pathway taken to reach that state.

Enthalpy (H)

The sum of the internal energy of a system and the product of pressure and volume.

Exothermic Reaction

A reaction that releases heat, resulting in a negative enthalpy change (ΔH < 0).

Endothermic Reaction

A reaction that absorbs heat, resulting in a positive enthalpy change (ΔH > 0).

Bond Energy

The amount of energy required to break one mole of a bond in a compound.

Thermal Equilibrium

The state when two objects in thermal contact reach the same temperature.

Calorie (cal)

The amount of energy needed to raise the temperature of one gram of water by 1 °C.

Joule (J)

The amount of energy needed to move a 1 kg mass a distance of 1 meter.

Heat Exchange

The transfer of thermal energy between a system and its surroundings.

Specific Heat Capacity (Cs)

The amount of heat required to raise the temperature of 1 gram of a substance by 1 Kelvin.

Hess's Law

The total enthalpy change for a reaction is the sum of the enthalpy changes for the individual steps of the reaction.