An Investigation into the Effect of Changing the Concentration on the Rate of Reaction

An investigation into the effect of changing the concentration on the rate of reaction

Aim:

To investigate into the effect of changing the concentration on the rate of reaction

Variables:

· Keep the same volume

· Keep the same length of magnesium

· Change the amount of acid

· Change the amount of water

Method:

· Set up apparatus as shown

· Add 30ml of hydrochloric acid into the beaker

· Measure 5cm of magnesium

· Add the 5cm of magnesium to the hydrochloric acid

· Put a bong onto the conical flask

· Start timing

· Measure the amount of gas collected every 10 seconds for 2 minutes

Diagram:

Prediction:

I predict that as the concentration of the Hydrochloric acid increases, the time taken for the magnesium to dissolve decreases. So, the higher the concentration of the acid, the faster the reaction between magnesium ribbon and the hydrochloric acid will be. This would be because there were more acid molecules to react with the magnesium ribbon. Increasing the concentration of the reactants will increase the frequency of collisions between the two reactants

Hydrochloric acid + Magnesium Magnesium chloride + Hydrogen

Preliminary results:

Magnesium Acid 10 20 30 40 50 60 10 20 30 40 50 60

5cm 30ml 4 15 34 45 55 - - - - - - -

2cm 30ml 5 10 14 17 22 26 32 37 40 45 47 49

2cm 20ml 1 5 6 9 12 14 16 18 20 22 23 25

From my preliminary results, I can see that the higher the acid concentration and the longer the magnesium, the faster the reaction time will be.

After I had taken my preliminary results I could see that they were not being taken accurately, therefore we changed the method. Instead of using a delivery tube and a measuring cylinder to measure how much gas was collected, we used a gas syringe. This made our results more accurate.

Scientific theory:

If the concentration of a dissolved reaction is increased or the pressure of a reacting gas is increased, the more particles there will be in the same volume.

The more reactant particles there are, the greater chance of them colliding, consequently, there will be more collisions meaning the