TOPIC C5 ENERGY CHANGES

Question 1

what is an exothermic reaction

Answer 1

-transfers energy to the surroundings by heating
-shown by a rise in temperature

Question 2

state 2 examples of exothermic reactions

Answer 2

-neutralisation reactions (acid + alkali)
-oxidation reactions, e,g adding sodium to water releases energy

Question 3

state the best example of exothermic reaction

Answer 3

burning fuels
-combustion
-gives out loads of energy

Question 4

endothermic reaction

Answer 4

a reacction which takes in energy from surroundings and is shown by a fall in temperature

Question 5

what do endothermic reactions include

Answer 5

-reaction between citric acid and sodium hydrogencarbonate
-thermal decomposition

Question 6

an example of an endothermic reaction

Answer 6

-used in sport injury packs
-chemical reaction allows the ice pack to become instantly cooler

Question 7

what are reaction profiles

Answer 7

diagrams to show relative energies of reactants and products in a reaction
-how the energy changes over the reaction

Question 8

bond breaking is a

Answer 8

endothermic process
-as energy must be supplied to break existing bonds

Question 9

bond forming is a

Answer 9

exothermic process
-energy released when new bonds are formed

Question 9

state which reaction releases more energy by forming bonds

Answer 9

exothermic reaction

Question 10

bond energy calc