Rates of Reaction

Whether the strength of Hydrochloric acid will affect the speed of the

rate of reaction when reacting with Magnesium Ribbon.

I want to find out whether the strength of Hydrochloric acid will

affect the speed of the rate of reaction when reacting with Magnesium

Ribbon.

Variables

There are two important independent variables in my investigation the

first of which is the concentration of the Hydrochloric Acid used

during the investigation. The concentration of the acid will partly

determine how fast the reaction takes place, if we put some of the

magnesium ribbon into the HCL at 2molar then it might have simply

dissolved within a few seconds and then I would not have had time to

record down any decent enough results to plot a graph with. The other

important independent variable that will affect the speed of the rate

of reaction is the length of magnesium ribbon. We need to put enough

Mg Ribbon into the HCL so that it doesn’t run out straight away but

also so that the experiment stops by itself once the gas syringe has

filled up.

The reasons for choosing these two independent variables are that it

would be too hard to try and find a catalyst for this experiment; a

catalyst is a substance that increases the rate of a chemical reaction

without being consumed in the reaction. Finding a catalyst for this

particular experiment could take months never mind the amount of time

we have been given for our experiment.

The independent variable that I will change is going to be the

hydrochloric acid, we will use 50ml of HCL at the following molarity

concentrations; 2molar, 1.6molar, 1.2molar, 0.8 molar and 0.4 molar. I

have decided to experiment with these different strengths of molar

because I think it will give a wide set of results to put into a

graph.

The dependant variable I shall be measuring will be the time it takes

for the magnesium to completely react with the hydrochloric acid, I

shall record the times for each concentration of hydrochloric acid

three times so that it makes it a fair test.

To ensure the investigation is fair we will use the same length of

magnesium ribbon for all the different strengths of hydrochloric acid

and the length will be the one that we picked out from the preliminary

experiments. Another way in which we will keep the investigation fair

will be to carry out an experiment at each concentration of

hydrochloric acid three times so that we can then get hopefully around

the same outcome from each experiment, and if there are any anomalies

we can try to explain why they happened.