ENERGYPG. 68-72

LO: I CAN DESCRIBE ENERGY IN FORM, UNITS, AND EXPLAIN ENERGY

CHARACTERISTICS OF CHEMICAL REACTIONS.

WHAT IS ENERGY?

DefinedEnergy is…

The capacity to do work.

Work is…The result of force

acting on a distance (doing something).

TYPES OF ENERGYKinetic Energy: The energy of movementPotential Energy: The energy associated with position or composition.

Methane (CH4)

TYPES OF ENERGYKinetic Energy: The energy of movementPotential Energy: The energy associated with position or composition.

TYPES OF ENERGYElectrical Energy: Energy associated with the flow of electric charge (electricity/batteries).

Thermal Energy: Energy associated with the random motions of atoms/molecules in matter (heat).

TYPES OF ENERGY

Radiant Energy

Chemical Energy: Energy associated with the positions (high energy bonds) b/w the particles that compose them (gasoline, sugars, etc.).

Radiant Energy: Energy of EM spectrum (sunlight, infrared, X-rays, UV radiation, etc.)

UNITS OF ENERGY• Joule = SI base

unit for energy (James Joule).

• calorie (cal) amt of energy to heat 1 g of water 1 degree Celsius.

• Cal = food calorie or 1000 cal.

ENERGY IN REACTIONS

Type of Reaction Change in Energy

Endothermic Absorbs energy as rxn takes place

Exothermic Releases energy as rxn takes place

Activation Energy The energy needed to get a rxn started

ENERGY IN REACTIONS

A

Where on the diagram do these three belong?

1)Products ___2)Reactants ___3)Activation

Energy ___

B

C

Time

En

erg

y

ENERGY IN REACTIONS

ENERGY IN REACTIONSEndo or Exo? H= Hp -

Hr

Reactants Products1. 237 J 30 J

2. 332 J 567 J