Energy Changes

Question 1

In an exothermic reaction, is heat transferred to or from the surroundings?

Answer 1

To the surroundings

Question 2

Name two different types of reaction that are exothermic.

Answer 2

Combustion

Neutralisation

Question 3

Define what is meant by an endothermic reaction.

Answer 3

A reaction that takes in energy (heat) from its surroundings.

Question 4

What is the purpose of putting the reaction container into a beaker containing cotton wool during an experiment to investigate the temperature change of an exothermic reaction?

Answer 4

To reduce the energy/heat lost to the surroundings by insulating it.

Question 5

What is the activation energy of a reaction?

Answer 5

The minimum amount of energy the reactants need to collide with each other and react.

Question 6

True or false? In an endothermic reaction, the products have more energy than the reactants.

Answer 6

True

Question 7

Fill in the blanks:

Bond breaking is an ______ process.

Answer 7

Endothermic

Question 8

Fill in the blanks:

Bond forming is an ______ process.

Answer 8

Exothermic

Question 9

Fill in the blanks:

In an ______ reaction, the energy released by forming bonds is greater than the energy used to break them.

Answer 9

Endothermic

Question 10

What three steps would you use to find the overall energy change in a reaction if you were given the known bond enthalpies for the bonds present in the reactants and products?

Answer 10

1. Find the energy required to break the original bonds.
2. Find the energy released by forming the new bonds.
   Overall energy change = 1 - 2