4.3.5 - effect of catalysts Flashcards
1
Q
what are catalysts?
A
- increase rate
- remain chemically unchanged
2
Q
catalysts increase rate because:
A
- 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
3
Q
how can the effect of a catalyst on rate be demonstrated?
A
by using the decomposition of hydrogen peroxide
4
Q
how long is the hydrogen peroxide experiment without a catalyst
A
very long, could take days to finish - slow reaction
5
Q
what catalyst is used in the hydrogen peroxide experiment?
A
manganese (IV) oxide
6
Q
how long is the hydrogen peroxide experiment with a catalyst
A
very short, takes only a few seconds to finish
7
Q
variables for the hydrogen peroxide experiment
A
independent - which catalyst is being used
dependent - volume of O2
control -
volume + concentration of H2O2
temperature
mass + surface area of a catalyst
