C5

Question 1

In an exothermic reaction is the heat transferred to or from the surroundings.

Answer 1

to the surroundings

Question 2

name 2 different types of reactions which are exothermic

Answer 2

combustion and neutralisation reactions

Question 3

define what is meant by an endothermic reaction

Answer 3

a reaction that takes in energy from its surroundings

Question 4

write down the equation for the thermal decomposition of calcium carbonate

Answer 4

(calcium carbonate) CaCO3 (+ heat) –> CO2 (carbon dioxide) + Cao (quicklime)

Question 5

what is the purpose of putting the reaction container into a beaker containing cotton wool during an experiment to investigate the temperature change of an exothermic reaction.

Answer 5

to give more insulation and to reduce the amount of energy lost by evaporation, so the energy isn’t lost into the surroundings

Question 6

what is the activation energy of a reaction.

Answer 6

the initial rise in energy/ amount of energy needed to start a reaction.

Question 7

True or False: in an endothermic reaction, the products of the reaction have more energy then the reactants

Answer 7

True

Question 8

in the following sentences either use endothermic or exothermic to fill in the gaps.
1) a bond breaking is an __ process
2) a bond forming is an __ process
3) in an __ reaction the energy released by the forming bonds is greater then the energy used to break them

Answer 8

1) endothermic
2) exothermic
3) exothermic