Edexcel GCSE Combined Science CC7 Rates of reaction and energy changes overview quiz quiz

Lower temperature

Larger pieces of solid

Higher concentration

Removing a catalyst

The total amount of energy released to the surroundings by the reaction

The total energy of the products

The energy stored in a catalyst

The minimum energy particles need to collide successfully

Particles move faster, colliding more often and with more energy reaching the activation energy

Particles move more slowly, so they collide far less often and almost never reach the activation energy

It lowers the overall concentration of the reacting particles in the mixture

It uses up the catalyst much more quickly than usual

By raising the activation energy needed for the particles to react

By providing a pathway with a lower activation energy

By being used up steadily as the reaction proceeds

By increasing the concentration of the reactants

2 cm3/s

8 cm3/s

4 cm3/s

1600 cm3/s

Endothermic

Neutral

A catalyst

Exothermic

Below the reactants

Above the reactants

At the same level as the reactants

There are no products

It decreases

It increases

It stays the same

It disappears

It increases

It stays the same

It decreases

It becomes zero

They each have just one electron in their outer shell

They are reactive metals like the alkali metals

They have no electrons in their atoms at all

They have full outer electron shells

It decreases until the reaction stops

It increases steadily as the reaction goes on

It stays constant throughout the whole reaction

It restarts once the reactants run out

Nothing happens because bromine is more reactive than chlorine and will not be displaced

Chlorine displaces bromine because chlorine is more reactive

The potassium is displaced from the solution

The solution simply turns completely colourless