Catalysts

Question 1

what is a catalyst

Answer 1

a substance which increases the rate of reaction, without being chemically changed or used up

Question 2

even though we use a catalyst, why does the reaction equation remain the same

Answer 2

because a catalyst doesnt change the products of a reaction, especially because it isnt used up

Question 3

if a catalyst isnt used up, how can it be effectively used in reactions

Answer 3

only a tiny bit needs to be used in order to catalyse large amounts of reactants

Question 4

what do catalysts specifically do and why

Answer 4

• by decreasing the activation energy needed for a reaction to occur
• by providing an alternative reaction pathway that has a lower activation energy

Question 5

what is the result of a catalyst providing an alternative reaction pathway which has a lower activation energy

Answer 5

more of the particles have at least the minimum amount of energy needed for a reaction to occur when the particles collide

Question 6

what do reaction profiles show

Answer 6

the energy levels of the reactants and the products in a reaction

Question 7

what would a reaction profile show

Answer 7

• the graph would be energy against progress of reaction
• a straight line, being the reactants, would be drawn on the graph
• until the reaction takes place, showing the energy needed for the reaction to happen (y axis)
• then energy levels dropping and the line plateuing, showing the products

Question 8

what two lines would a reaction profile show and how would they look

Answer 8

• the reactant line will split off into two lines
• one showing the activation energy without a catalyst
• and the other showing the activation energy with a catalyst
• the line showing the with catalyst would be below the other one
• as a catalyst reduces the activation energy needed for a reaction to take place

Question 9

what are enzymes in terms of this topic

Answer 9

biological catalysts

Question 10

what do enzymes do if they are catalysts that are biological

Answer 10

they speed up the chemical reactions in living cells

Question 11

what reactions are catalysed by enzymes

Answer 11

• respiration
• photosynthesis
• protein synthesis

Question 12

what are enzymes from yeast cells used for and how do they do it

Answer 12

• they are used in the fermentation process which is used to make alcoholic drinks
• they catalyse the reaction that converts sugars into ethanol and CO2