The results of this show that I should use the small chips as it would take too long to use either of the other two sizes.
Then I repeated the experiment with the highest concentration to see which size marble chips would be too fast.
These results showed me that using the small chips will still be satisfactory so I will use them.
I used 3g of the chips each time which worked well but I will see if using a lower or a higher mass of chips would be better
There doesn’t seem to be a lot of difference in the results for the 3 experiments so I shall just use the 3g as they are mid way in between the two results.
I used 50cm³ of solution each time which worked well but I will see if a lower or a higher volume of solution would be better
The first results (using 20cm³) seemed to run out of acid so I will not use this, however, the other 2 appear to be relatively the same because both had the same amount of chips to work with and therefore will produce at around the same rate.
Prediction
A reaction occurs when particles collide. I predict that the higher the concentration of Hydrochloric acid, the faster the rate of reaction will be. I have predicted this because the higher the concentration of Hydrochloric acid means the higher the amount of acid particles there are in the solution and therefore there is a much greater chance of the acid particles colliding with the chips, therefore speeding up the rate of the reaction. Whereas, if the solution was much more dilute, the particles would need to travel a lot further in order to collide with one another, because there wouldn’t be as many of them. I also think that if the number of acid particles in the solution in doubled then the rate would double also as there is twice the chance of collision of the particles.
This is what I predict the graph will look like when I have drawn up the results.
Method
The apparatus were up as shown:
To ensure reliability, each concentration was repeated 3 times and the average found. As soon as the 3g of small chips were added to the solution, the stop watch was started. It was then stopped when the gas syringe reached 50cm³.
The solutions were set up in the ratios below, 100cm³ of the solution was used to make it easier to work out the ratios, and the more the solution doesn’t make much of a difference to the experiment results, as shown in the preliminary results. 2Molar Acid was used to get a wider spread of results.
Results
Conclusion
In conclusion, my prediction was correct, the higher the concentration of acid, the faster the rate of the reaction is. This is because if there is a high concentration of acid it means that there are more acid particles for the chips to collide with therefore the faster that the acid particles are going the find the chips therefore the faster the rate of reaction.
This is all shown in the graph, which also states the rates at which the reactions have taken place.
Evaluation
There were no anomalous results in the experiment. A few points were slightly off of the line of best it but no enough to call them anomalies.
The test was as fair as I could have made it given the equipment in school.
The chips were weighed to as close to 3g as possible but with only 2 decimal places to work to and no way of splitting the chips a lot of the experiments were one or two grams under/over weight.
Also the temperature varied slightly when I did each experiment which could have made a slight error in the results, to resolve this I could have sat the whole experiment in a water bath with a controlled temperature.
As a further experiment I think I could have investigated how changes in temperature affect the rate of reaction, whether one or two degrees actually make a lot of difference. I could use a water bath to keep the experiment in and very the temperature of the water in it slightly to see how it affects the rate of reaction.
