SPEEDING UP and SLOWING DOWN rates of reaction.

Reactions can be speeded up by:

1. Using reagents that are either:-

(THIS IS NOT THE SAME AS USING MORE REAGENTS)

2. Increasing the TEMPERATURE at which a reaction occurs – generally for every 10oC rise in temperature the reaction rate doubles.

3. Using reagents that are finely divided – POWDERS generally work faster than LUMPS.

They have a BIGGER SURFACE AREA.

4. Using a CATALYST – this can generally speed up or slow down the rate at which a chemical reaction occurs.

Reactions can be slowed down by:

1. Using reagents that are either:-

(THIS IS NOT THE SAME AS USING LESS REAGENTS)

2. Reducing the TEMPERATURE at which a reaction occurs i.e COOL things down.

3. Using reagents that have a SMALL SURFACE AREA i.e the substance is in LARGE LUMPS.

4. Using a CATALYST – the right catalyst can slow down the rate at which a chemical reaction occurs.

EXPLANATION: THE COLLISION THEORY

If the particles making up the substances are to react with one another they must hit each other

If both things occur the collision is said to be EFFECTIVE.

So NO reaction will occur if:

No reaction will be seen to occur if not enough particles react.

Reactions generally slow down as the reaction proceeds because: