Energy

Question 1

Law of Conservation of Energy?

Answer 1

The total energy in a system cannot be created nor destroyed, only transformed from one form to another. The energy can also be transferred from one place to another.

Question 2

Exothermic Reactions? Give an example.

Answer 2

Reactions which transform chemical potential energy into thermal energy. ΔE is (-). Net energy released to surroundings as heat, and therefore, products have less chemical potential energy than the reactants. All fuels release heat; combustion and respiration are exothermic reactions.

Question 3

Endothermic Reactions and list an example?

Answer 3

Reactions which transform thermal energy into chemical potential energy. ΔE is (+). Net energy is absorbed from the surroundings, making it colder. Net energy absorbed and stored in bonds of products, therefore products have more chemical potential energy than the reactants. Photosynthesis is endothermic.

Question 4

Heat of Reaction (Enthalpy).

Answer 4

The net change of the chemical potential energy of a system.

Question 5

Activation Energy?

Answer 5

The minimum energy required to start a chemical reaction or the energy required to form the activated complex.

Question 6

Activated Complex?

Answer 6

A high energy, unstable temporary transition state between reactants and products.

Question 7

Catalyst?

Answer 7

A substance that increases the rate of the reaction but remains unchanged at the end of the reaction.