rates of reaction and energy changes

Question 1

are these reactions exothermic or endothermic?

• neutralisation
• displacement
• precipitation

Answer 1

• neutralisation: exothermic
• displacement: exothermic/ endothermic
• precipitation: exothermic

Question 2

what is an exothermic reaction and what examples it?

Answer 2

an exothermic rection is one that transfers energy into the surroundings so the temperature of the surroundings increases e.g. combustion, hand warmers

Question 3

what is an endothermic reaction and what are examples of it?

Answer 3

an endothermic reaction is one that takes in energy from the surroundings so the temperature of the surroundings decrease e.g. injury packs

Question 3

what type of reaction is breaking of bonds and why?

Answer 3

endothermic as energy needs to be supplied in in order to break the bonds

Question 4

what type of reaction is making of bonds and why?

Answer 4

exothermic as energy is released in order for the bonds to be formed

Question 5

what is meant by the term activation energy?

Answer 5

the minimum amount of energy that particles must have to react

Question 6

how do you measure the rate of reaction?

Answer 6

rate of reaction= amount of reactant used/product formed / time

Question 7

what are 5 things you can do to increase the rate of reaction?

Answer 7

• temperature
• pressure
• concentration
• surface area
• catalyst

Question 8

how does increase temperature affect the rate of reaction?

Answer 8

there is more energy in the particles so the collide more frequently and more successful collisions

Question 9

how does increase pressure affect the rate of reaction?

Answer 9

increases the number of particles in a volume so there is more frequent collisions

Question 10

how does increase concentration affect the rate of reaction?

Answer 10

there is more particles in a volume so it increases the amount of collisions and therefore more successful collisions

Question 11

how does increase surface area affect the rate of reaction?

Answer 11

there is more frequent collisions so more successful collisions

Question 12

what is a catalyst?

Answer 12

a substance that speeds up the rate of reaction without changing or being used up

Question 13

what is an enzyme?

Answer 13

a biological catalyst

Question 14

what is yeast?

Answer 14

the enzyme used in the production of ethanol which is used in alcoholic drinks