The Basics
The transfer of thermal energy from a warm object to a cooler object
Heat
A measure of the average kinetic energy of entities in a substance
Temperature
A device that is used to measure thermal energy changes in a chemical or physical change
Calorimeter
A system in which both matter and energy are free to enter and leave the system
Open System
A reaction that releases energy to the surroundings
Exothermic
The energy of a body or system due to its position or composition
Potential Energy
The ability to do work; SI units joules (J)
Energy
A group of reactants and products being studied
Chemical System
The quantity of heat required to vaporize one mole of a liquid
Molar Heat of Vaporization
The quantity of thermal energy required to raise the temperature of 1 g of a substance by 1° C; SI units J/(g·°C)
Specific Heat Capacity (c)
Energy cannot be created or destroyed, it can only be transformed from one form into another.
Law of Conservation of Energy
The energy required to break a given chemical bond
Bond Dissociation Energy
The energy released to or absorbed from the surroundings during a chemical or physical change
Enthalpy Change (∆H)
A system in which energy can enter and leave the system but matter cannot
Closed System
The enthalpy change associated with a particular chemical reaction units kJ/mol
Molar Enthalpy Change (∆rH)
The study of the energy changes that accompany physical or chemical changes in matter
Thermochemistry
The amount of energy transferred by a force over a distance; SI units joules (J)
Work
All the matter that is not part of the system
Surroundings
An ideal system in which neither matter nor energy can move in or out
Isolated System
A graph showing the temperature changes a substance undergoes while the substance is heated
Heating Curve
The energy of an object due to its motion
Kinetic Energy
The total quantity of kinetic and potential energy associated with the motion of particles in a substance
Thermal Energy
The most stable form of a substance under a standard conditions 25 °C and 100 kPa.
Standard State
The total amount of thermal energy in a substance
Enthalpy (H)
The enthalpy change for the conversion of reactants to products is the same whether the conversion occurs in one step or several steps.
Hess’s Law