4.7 Exothermic And Endothermic Reactions

Question 1

What are reactions that transfer energy to the surroundings called? Do they make or break bonds?

Answer 1

Exothermic reactions, they make bonds which releases energy so the surrounding temp increases

Question 2

Name 3 types of exothermic reactions:

Answer 2

• combustion, such as burning fuels
• oxidisation, such as respiration
• neutralisation reactions involving acids and bases

Question 3

How can you tell that burning a natural gas is an exothermic reaction?

Answer 3

It heats the surroundings

Question 4

What are reactions that transfer energy from the surroundings called? Do they make or break bonds?

Answer 4

Endothermic reactions, they break bonds which requires energy so the temp decreases

Question 5

Name an endothermic reaction

Answer 5

Thermal decomposition

Question 6

Why do thermal decomposition reactions need to be heated continuously to keep the reaction going?

Answer 6

They need lots of energy to break the bonds so need lots of heat energy or the reaction will stop completely

Question 7

What are the 2 ways that show a reaction is endothermic?

Answer 7

• cools the surroundings

* needs to be heated to keep going

Question 8

Why is energy transferred in chemical reactions?

Answer 8

Bonds are broken and made