C7

Question 1

Exothermic reaction ?

Answer 1

reaction that gives out heat

Question 2

2 examples of exothermic reactions ?

Answer 2

self heating cans

hand warmers

Question 3

2 uses of exothermic reactions

Answer 3

combustions

neutralisation

Question 4

endothermic ?

Answer 4

takes in heat energy - surrounding get colder

Question 5

example of an endothermic reaction

Answer 5

sports injury pack

Question 6

Experiment of measuring the energy released from a chemical reaction

Answer 6

polysterine cup
insulated lid
thermometer
mixed chemicals

Question 7

the required practicals steps

Answer 7

25cm3 of the chemical
check temperature
add 2nd chemical nd stir
check temperature again

Question 8

main errors made in the practical ?

how can this be reduced ?

why is the mixture stirred ?

Answer 8

some energy gets to escape

insulate the beaker + put lid on

to make sure its got even heating (no cold spots)

Question 9

activation energy ?

Answer 9

energy needed to start a chemical reaction

Question 10

reaction profile for exo

Answer 10

reactant starts higher drops down to product

Question 11

reaction profile for endo

Answer 11

reactants starts low nd raised then drops a little to the product

Question 12

bond breaking and making

Answer 12

more energy is released when the new bonds are formed than is put in to break the old bonds

Question 13

for endo reactions bond breaking

Answer 13

more energy is put into break the old ones