Year 11 – Paper 2 - Chemistry Knowledge Organiser – Rate of reaction

Question 1

Temperature

Answer 1

The hotter the particles are, the faster they move and
therefore the frequency of successful collisions is greater.

Question 2

Pressure and concentration

Answer 2

More particle in the same space means that collisions
happen with greater frequency.

Question 3

Catalysis

Answer 3

Catalysts are substances that speed up the rate of a
reaction without being used up themselves. They work by
lowering the activation energy. This is the amount of
energy needed to get a reaction going. Just like striking a
match, you need to put some energy into it, the match will
not just burst into flames by itself. The graph to the right
shows an energy profile of a catalysed reaction when ncompared to the same one that is not catalysed

Question 4

Surface area

Answer 4

If there are more particles exposed to the reactants then
the frequency of successful collision is greater.

Question 5

Reversible Reactions

Answer 5

Reversible reaction are ones that will react
in both directions.
This means that as quickly as products are
formed they can be turned back into
reactants.
Reversible reactions are identifiable by the
arrow in the middle of the reaction.

Question 6

Factors effecting the rate of a reaction

Answer 6

There are several factors that can effect the rate of a
chemical reaction, however it essentially boils down to
increasing the amount of successful collision.

Question 7

Collision theory

Answer 7

Why do things react in the first place?
Things will only react if the particles collide with
enough energy to cause a effective collision. This
is best illustrated in the diagram to the right. A
faster reaction will have a higher frequency of
collisions with sufficient energy

Question 8

Calculating the Rate of Reaction

Answer 8

The rate of a reaction can be found by the equation below.
This is the same as saying on a graph like the one shown that the change in Y / the change in X = the rate of a reaction.
The line is curved.
This means that
the rate of
reaction changes
as it progresses.

Question 9

Rate of Reaction

Answer 9

The rate of a reaction means how quickly reactants are turned into the
products.
If this happens quickly then you have a high rate of reaction, if it takes a long
time then you have a slow rate of reaction.
An example of a slow reaction could be rusting
An example of a fast reaction could be an explosion.