Energy changes - exo and endothermic reactions

Question 1

what is an exothermic reaction

Answer 1

a reaction which transfers energy / heat to it’s surroundings

Question 2

how can we tell if a reaction is exothermic

Answer 2

the temperature of surroundings is hotter than when it started

Question 3

how can we tell if a reaction is endothermic

Answer 3

there is a fall in temperature

Question 4

examples of exothermic reactions

Answer 4

• combustion
• neutralisation
• many oxidation reactions
• respiration

these reactions give off energy

Question 5

examples of endothermic reactions

Answer 5

• photosynthesis

- thermal decomposition

Question 6

what are reaction profiles

Answer 6

diagrams that show the relative energies of the reactants and products in a reaction

Question 7

how is an exothermic reaction shown in a reaction profile

Answer 7

products are at a lower energy than reactants

Question 8

what is activation energy

Answer 8

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

Question 9

how is an endothermic reaction shown in a reaction profile

Answer 9

products are at a higher energy than reactants

Question 10

how to find bond energies

Answer 10

energy required to break - energy required to make

Question 11

examples of exothermic reactions we use in daily life

Answer 11

• hand warmers
• self heating cans

Question 12

what requires energy

Answer 12

breaking a bond

Question 13

what releases energy

Answer 13

making a bond