Thermochemistry

Exothermic Reaction

• Gives off energy

• Combustion reactions

• Negative ΔH

Endothermic Reaction

• Absorbs energy

• Energy but be added to the reactants for the reaction to occur

• Positive ΔH

Potential Energy

• The stored energy

• The ability of a system to do work due to its position or structure (bond energy)

Kinetic Energy

Extra energy due to motion (work needed to accelerate from rest to current velocity

Solid Kinetic Energy

Vibrational Motion

Liquid Kinetic Energy

Rotational Motion

Gas Kinetic Energy

Translational Motion

Temperature

the measurement of the average kinetic energy of the molecules

Thermal Energy

• The total potential and kinetic energy of an object has a result of the random motion of the particles.

• Objects possess this and not heat

Heat

The thermal energy transferred from one object to another (q)

Chemical System

The reactants and products being studied

Surroundings

The matter that is not part of the system

Open System

• Can change mass

• Can change energy

• usually in the form of heat with its surroundings

Closed system

• Allows the transfer of energy (heat)

• but not mass

Isolated system

• does not allow the transfer of either mass or energy

Physical Change - Nuclear NRG (Not learning in class)

changes the arrangement of the molecules

chemical change Nuclear NRG (Not learning in class)

changes the electronic structure of the molecules

nuclear change - Nuclear NRG (Not learning in class)

changes the nuclei of the atoms

Gas Production

Measure for volume or pressure

Ion production

conductivity

Color change

Spectrophotometer

pH Change

Hydrogen Concentration

Mass Change

if a gas is produced that cannot be collected we can monitor the change in mass