I then measured to see how long it would take to gain 100 cm3 of CO2 using a stopwatch and a gas syringe. To make sure the gas syringe is working properly I must make sure that the clam is not on too tight or it will affect the outcome of the results. To obtain the most reliable results I will do each experiment three times.
I predict that the high molarity concentration solution will have a much faster rate of reaction than the weaker solution. I have predicted this from my knowledge of a previous experiment and scientific knowledge. The previous experiment I did was adding Sodium Thiosulphate to Hydrochloric Acid Sodium Chloride + Sulfur Dioxide + Sulfur + Water. We were going to see how long it takes to produce enough sulfur to obscure a black cross under a beaker when we looked through the solution. The results we achieved was as follows:
I think that the results of the marble chips and HCl experiment will show the same results as this Sodium Thiosulphate experiment. As the higher the concentration the increased amount of ions per cm3 and therefore more frequent collisions between them, which then makes the experiment react faster. Another reason I think that the rate of reaction will increase is that the experiment is exothermic, this means that it will give itself more energy and therefore more collisions and faster collisions. Also in the 2.0M solution compared with the 0.5M solution there are much more HCl particles in the same volume so the are going to collide with each other more often.
Obtaining evidence
The equipment I am going to use for the experiment is:
Clamp – needs to hold the gas syringe.
Conical Flask – this needs to hold the HCl and marble chips while they are reacting and need to have a bung leading to the gas syringe.
Gas Syringe – this is very accurate and will therefore give me precise results.
Measuring Beaker – this helps me measure out thee different amounts of HCl and distilled water.
Distilled Water – this will be used to dilute the HCl.
Pan Balance – this will be used to measure out the marble chips to 20 grams.
Pipette – this will be used to measure out the HCl and distilled water very carefully.
Stopwatch – to time how long it takes to get 100 cubic centimetres of carbon dioxide.
HCl
Marble Chips
Analyzing Evidence and Drawing Conclusions
From looking at my results and graph I am able to conclude that the more concentrated the acid the quicker the reaction happened and the faster the gas was produced. This is as I predicted and I think they match quite well as the rate of reaction graph is basically a straight line and the average time graph has an increasing gradient.
Evaluating Evidence
Overall this was a very successful experiment and everything went very smoothly, and that was why my results were very good, and I am able to make the conclusion that the higher the concentration the faster the rate of reaction.
From looking at my results I can see that there were no poor results, which was a good thing, and it proves that everything went very well. There was no real source of error in the equipment. The only possibility was if the temperature of the acid had changed from when we did the first reading to the finish.
