The Rate of Reaction Between Marble Chips and Hydrochloric Acid

I will set out my equipment as shown in the diagram below:-
Throughout the experiment I was ready with the stopwatch, so that I started and stopped it immediately it was necessary to get accurate readings.
Once I have set up the apparatus I will measure out 5cm3 of acid in a measuring tube and then pour it into the conical flask. I will quickly place the chips into the acid, insert the bung in the top of the boiling tube and start the stopwatch. This must be done in as short a space of time as possible. From then on, I must take the reading of the volume in the gas syringe after a certain point is reached. I used eight different molarities of hydrochloric acid and then recorded the amount of carbon dioxide in the gas syringe. I will accurately record these roughly in...