Energy changes (P1)

Question 1

Endothermic

Answer 1

• energy taken from the surroundings

- temperature of the surroundings decrease

Question 2

examples of endothermic

Answer 2

• thermal decomposition

- spots injury packs

Question 3

Exothermic

Answer 3

• energy is transferred to the surroundings

- temperature of the surroundings increases

Question 4

examples of exothermic

Answer 4

• combustion

- hand warmers

Question 5

reaction profile

Answer 5

shows the overall energy change of a reaction

Question 6

breaking bonds in reactants

Answer 6

endothermic

Question 7

making bonds in products

Answer 7

exothermic

Question 8

overall energy change of a reaction - exothermic

Answer 8

-energy released making new bonds is greater than energy taken in breaking existing bonds

Question 9

overall energy change of a reaction -endothermic

Answer 9

-energy needed to break existing bonds is greater than the energy released making new bonds

Question 10

what has to happened for activation energy to be needed

Answer 10

chemical reactions only happen when particles collide with sufficient energy

Question 11

what is activation energy

Answer 11

the minimum amount of energy that colliding particles must have In order to react

Question 12

Endothermic reaction profile

Answer 12

• products have higher energy levels than reactants
• as the reactants form products, energy is transferred from the surroundings to the reaction mixture
• temp of surroundings decrease because energy is taken away In the reaction

Question 13

Exothermic reaction profile

Answer 13

• products have lower energy level than reactants
• when the reactants form products energy is transferred to the surroundings
• temp of surroundings increases because energy is released in this reaction