Energy Changes

Question 1

Exothermic or endothermic: Combustion

Answer 1

exo

Question 2

Exothermic or endothermic: oxidation

Answer 2

exo

Question 3

Exothermic or endothermic: hand warmers

Answer 3

exo

Question 4

Exothermic or endothermic: thermal decomposition

Answer 4

endo

Question 5

Exothermic or endothermic: neutralisation

Answer 5

exo

Question 6

Exothermic or endothermic: sports injury pack

Answer 6

endo

Question 7

Exothermic or endothermic: fireworks

Answer 7

exo

Question 8

Exothermic or endothermic: reaction of citric acid and sodium hydrogencarbonate

Answer 8

endo

Question 9

Exothermic or endothermic: self heating cans

Answer 9

exo

Question 10

Exothermic or endothermic: the reaction between zincc and copper sulfate

Answer 10

exo

Question 11

To break any chemical bond what is needed

Answer 11

energy

Question 12

breaking bonds is

Answer 12

endo

Question 13

making bonds is

Answer 13

exo

Question 14

Practical measuring energy changes/ investigating energy changes steps

Answer 14

Place polytyrene cup inside glass beaker for stability (can also add a polystyrene lid to ensure minimum heat loss)

Measure an appropriate volume of each liquid in the measuring cylinder eg 25 cm cubed

place one of the liquids in a polystyrene cup

record the temp of the solution

add the second solution and record the highest or lowest temp obtained, repeat the steps until. 5 spatulas(wait until the numbers on the thermometer have stopped moving then record)

Change your independant variable and repeat the experiment one more time

independant variable could be -
concentration of one of the reactants
type of acid / alkali being used
type of metal being used