Rates of Reaction

Sam Austin

Aim: An experiment to determine if changing the concentration of a reactant alters the rate of reaction.

Plan and Method

In the experiment we are going to undertake, we have to add to concentrates into a chronicle flask that have been very carefully measured to 10ml. These two concentrates are hydrochloric acid and Sodium Thiosulphate. When these two concentrates interact the solution slowly turns a white colour and when left long enough a faint yellow colour. Just as we place the two concentrates into the flask we begin timing to see how long it takes for the small black cross under the flask to disappear. Then we record the results onto a table. With in the experiment we will use 8 different concentrates these are 0.05, 0.1, 0.15, 0.2, 0.25, 0.3 and 0.4.

The equation for this experiment is:

Hydrochloric Acid -> Sodium Thiosulpahte -> Sulphur + Sodium Chloride + Water

We can tell when the reaction ends because the precipitate has stopped forming.

Equipment

• Conical Flask

• Pipette

• Measuring Cylinder (small)

• Measuring Cylinder (large)

• Heat proof mat

Risk Assessment

• Stand up at all times

• Wear goggles

• Hair tied back

• Tell the teacher when any accidents appear.

• Clear all chemical spillages up.

Fair Test

• Use different measuring cylinders for the solutions

• Wash both measuring cylinders and conical flask at least once after use.

• Same amount of solution each time

Preliminary Work

Concentration is the amount of particles in a solution.

High concentration is when there are lots of particles causing more collisions.

Low concentration is where there are smaller amounts

Of particles and less collisions.

Changing the concentration can affect the reaction, the higher the reaction the better the solution say fairy liquid and the reaction will be quicker. The less the concentration the slower the reaction.

A Molar is a very large number, approximately 600, 000, 000, 000, 000, 000, 000, 000.

Prediction

I