4.3.5 - effect of catalysts

Question 1

what are catalysts?

Answer 1

• increase rate
• remain chemically unchanged

Question 2

catalysts increase rate because:

Answer 2

• they provide an alternative route with a lower activation energy
• so the percentage of collisions with enough energy is higher
• so there are more successful collisions per unit time

Question 3

how can the effect of a catalyst on rate be demonstrated?

Answer 3

by using the decomposition of hydrogen peroxide

Question 4

how long is the hydrogen peroxide experiment without a catalyst

Answer 4

very long, could take days to finish - slow reaction

Question 5

what catalyst is used in the hydrogen peroxide experiment?

Answer 5

manganese (IV) oxide

Question 6

how long is the hydrogen peroxide experiment with a catalyst

Answer 6

very short, takes only a few seconds to finish

Question 7

variables for the hydrogen peroxide experiment

Answer 7

independent - which catalyst is being used
dependent - volume of O2
control -
volume + concentration of H2O2
temperature
mass + surface area of a catalyst