Rate of reaction - model answers

Front

How does the rate of a reaction change with time?

Back

Fastest at start of reaction: concentration of reactants is high so more frequent collisions.

Reaction slows down: concentration of reactants decreases, so less frequent collisions.

Reaction stops: no more reactant particles, so no collisions.

Front

How does Increasing the surface area of a reactant (solid) effect rate of reaction?

Back

  Increases the rate of reaction.

More particles available to react.

So more frequent collisions.

Front

How does Increasing the concentration of a reactant (solution) effect the rate of reaction?

Back

Increases the rate of reaction.

More particles in a given volume.

So more frequent collisions

Front

How does Increasing the pressure of a reactant (gas) effect the rate of reaction?

Back

Increases the rate of reaction.

More particles in a given volume.

So more frequent collisions.

Front

How does Increasing the temperature effect the rate of reaction?

Back

Increases the rate of reaction.

Particles have more kinetic energy.

More particles collide with energy above the activation energy.

So more frequent successful collisions.

Front

What is a catalyst?

Back

A catalyst is a substance that speeds up a chemical reaction but is not used up in the process.

Front

How does a catalyst work?

Back

Catalysts work by providing an alternative route for the reaction, involving a lower activation energy.