C5.5- Energy Changes

Question 1

What is an exothermic reaction?

Answer 1

A chemical reaction which transfers energy to thermal store of surroundings

Question 2

What is an endothermic reaction?

Answer 2

A chemical reaction in which energy is taken from the thermal store of the surrounding.

Question 3

What does a reaction profile look like for an exothermic reaction?

Answer 3

Reactants is higher and products is lower. Curve joins them and activation energy is the top of the curve.

Question 4

What does a reaction profile look like with an endothermic reaction?

Answer 4

Reactants is lower than products.

Question 5

What can you read from a reaction profile?

Answer 5

X-axis is reaction in progress. Y-axis is the energy in the chemical store of the reaction. The overall energy change is the change from reactants and products. The activation energy is the energy from the reactants to the top of the curve.

Question 6

What does BENDOMEXO stand for and mean?

Answer 6

Breaking bonds is endothermic, making bonds is exothermic.

Question 7

How do you find if an equation is exo or endothermic?

Answer 7

You find the total energy in the bonds of the reactants. Find the total energy in the bonds of the products. If the energy released from making the bonds is greater than the energy needed to break the bonds then it is exothermic.

Question 8

How do you find the change in energy in an equation?

Answer 8

Do left minus right. If it is positive it is endothermic, if it is negative it is exothermic.