Energy Change Definitions

Question 1

Define heat of reaction

Answer 1

Heat of reaction (delta h) is defined as the net change of chemical potential energy of the system.

Question 2

Define exothermic reaction.

Answer 2

Exothermic reactions are reactions which transform chemical potential energy into thermal energy.

Question 3

Define endothermic reactions.

Answer 3

Endothermic reactions are reactions that transform thermal energy into chemical potential energy.

Question 4

Is bond breaking endo or exothermic?

Answer 4

The breaking of bonds is endothermic whilst the formation of bonds is exothermic.

Question 5

Delta H is ___ for endothermic reactions.

Answer 5

Positive.

Question 6

Delta H is ___ for exothermic reactions.

Answer 6

Negative.

Question 7

Exothermic reactions ___ ___ and thus ___ the temperature of the reaction mixture.

Answer 7

1. Release heat

2. Increase

Question 8

Endothermic reactions ___ ___ and thus ___ the temperature of the reaction mixture.

Answer 8

1. Absorb Heat

2. Decrease

Question 9

How else can Heat of reaction be presented?

Answer 9

Energy of products - energy of reactants.