C2.5 Exothermic and endothermic reactions

Question 1

When chemical reactions occur…

Answer 1

Energy is transferred to or from the surroundings

Question 2

What is an exothermic reaction?

Answer 2

One that transfers energy to the surroundings, usually in the form of heat

Question 3

What are some examples of exothermic reactions?

Answer 3

Combustion, many oxidation reactions and neutralisation

Question 4

What are some everyday uses for exothermic reactions?

Answer 4

Self-heating cans and hand warmers

Question 5

What is an endothermic reaction?

Answer 5

One that takes energy from the surroundings, usually in the form of heat

Question 6

What is an example of an endothermic reaction?

Answer 6

Thermal decompositions

Question 7

What is an everyday use for an endothermic reaction?

Answer 7

A sports injury pack

Question 8

If a reversible reaction is exothermic in one direction…

Answer 8

it is endothermic in the opposite direction

Question 9

What is an example of a reversible reaction, which is endothermic one way

Answer 9

Heat blue hydrated copper sulfate crystals which when the water is dried off leaves white anhydrous copper sulfate powder

Question 10

What is an example of a reversible reaction, which is exothermic the other way

Answer 10

Add water to the white anhydrous copper sulfate powder to get the blue hydrated copper sulfate crystals back again