Chapter 14 ENERGY

Sunlight The sun is the source of most of the energy on Earth Sun is a nuclear fusion reactor, creates 4x10 26 W energy. 1.73x10 17 W is received by the Earth.

Kinetic and Potential Energy Potential energy-energy of position or arrangement. Examples, stick of dynamite, a rock at the top of a cliff.

Kinetic Energy Kinetic energy- is the energy of motion An exploding stick of dynamite, the rock falling off the cliff.

Energy can be converted from one form to another.

Energy and Chemical Reactions Heat of reaction-enthalpy Usually described as the heat of a reaction Change in temperature of a reaction Reactions tend toward lower energy

Activation energy Reactions usually need an input of energy to get started. This is called the activation energy

Catalyst A catalyst lowers this activation energy It is not affected or changed by the overall reaction

Exothermic Reactions Results in the release of energy to the environment Products are lower in energy than reactants Most spontaneous reactions are exothermic

Endothermic reactions Reactions in which energy is absorbed from the environment. Products are higher in energy than the reactants

Entropy Entropy- reactions tend toward a less order Natural tendency is to go from order to less order, energy is required to go tin the opposite direction. Most spontaneous reactions tend toward less organized products.

Sometimes Enthalpy and Entropy are against each other

Thermodynamics The study of the “motion of heat”

1 st Law of Thermodynamics Energy is conserved Energy can be neither created nor destroyed Also called “Law of conservation of energy”

2 nd Law of Thermodynamics Energy does not flow from a cool object to a warmer object Spontaneous reactions tend toward higher disorder.

Fossil Fuels