C2.5- energy of reaction

Question 1

Give 2 examples of exothermic reactions

Answer 1

Oxidisation

Combustion

Question 2

What is an endothermic reaction?

Answer 2

When chemicals absorb energy from the surroundings

Question 3

Give 2 examples of endothermic reactions

Answer 3

Photosynthesis
Chemical cool pack
Baking

Question 4

What do we mean by reversible reaction?

Answer 4

A reaction in which the reactants react to form products- but then the products can also react to form the original products

Question 5

What is an exothermic reaction

Answer 5

When energy is released by the chemicals

Question 6

How can a reversible reaction be made to go backwards by changing the temperature?

Answer 6

To encourage the exothermic direction- the condition needs to be high temperature

Question 7

How can reversible reactions be made to go forwards by changing the temperature?

Answer 7

To encourage the endothermic direction- the condition needs to be low temperature

Question 8

Describe an everyday use of exothermic reactions

Answer 8

Hand warmers(chemical ones) - oxidation
Pyrotechnics(fireworks)
Respiring(respiration)
Combustion
Neutralisation

Question 9

Describe an everyday use of endothermic reactions

Answer 9

Photosynthesis
Lemon and baking soda
Cooking- frying eggs etc
Thermal decomposition