The other factors that we have considered are:
- The temperature because when the particles have been heated up, they can collide more rapidly so that can speed up the reaction. There is more movement than usual.
- The mass (surface area) of the marble chips because there are more or less particles depending on which you choose but either can affect the outcome of the result.
- A possible catalyst to speed up the reaction because it could have devastating affects for our results.
The key factor in our experiment that we are going to change is the concentration, which we will have in 5 intervals: - 0.2, 0.4, 0.6, 0.8, 1.
Prediction
My hypothesis is the higher the concentration of acid, the quicker the rate of reaction because there are harmful particles that can break up the marble chips easily. There are more particles so there will be more collisions, which can decrease the time for the rate of reaction.
Scientific Knowledge
My theoretical explanation is that there are more particles in the same volume of a concentrated solution so there are more collisions. More collisions mean a faster rate of reaction. If the concentration doubles the number of collisions double and so the reaction rate doubles as well. If the concentration was 0.4 and there were 16 collisions and the rate of reaction was 0.5, then the concentration was 0.8 and there were 32 collisions so the reaction rate would be 1. This would prove the scientific knowledge that I have gained.
Apparatus
The equipment that we are going to use are as follows: - a stopwatch, a conical flask, two measuring cylinders, an ice cream tub, a bung, a clamp stand, 5grams of marble chips, 150ml of Hydrochloric acid and an ice cream tub full of water (up to outer bit).
Method
- Collect the equipment as mentioned above.
- Put the 5grams of marble chips in the conical flask.
- Put the measuring cylinder full of water in the ice cream tub full of water upside down.
- Put the tube in the measuring cylinder that is in the water.
- Get the clamp stand and attach the measuring cylinder to it.
- Get the other measuring cylinder and fill 10ml with Hydrochloric acid and 40ml of water.
- Put the solution in the conical flask.
- Put the bung on and start timing.
- Then when you have measured 20ml of carbon dioxide from the measuring cylinder, which is in the ice cream tub.
- Stop timing and record your results.
- Pour the dilute acid into a bowl and the chips into another bowl.
- Then do this experiment four more times, each time add 10ml more to the measuring cylinder and the rest water but for 100% don’t add any water.
Results
An example of one of the calculations I have done to get the rate of reaction is:
17+18+18 = 17.66… = 17.67 20/17.67 = 1.1318619 = 1.13
Conclusion
I have found out that when the concentration was increased, the rate of reaction has increased because of the higher concentration. I believe that the results agree with my prediction.
Evaluation
I did have some anonymous results even though I did everything that the method told me in the right order but I did not have an explanation for these results. I think that my results are good overall because they prove what I predicted and that means that the rate of reaction increases when the concentration increases. In my opinion, we could not make the accuracy of the method any higher because there was no need to make it more accurate. We could of done the measuring of the dilute Hydrochloric acid in intervals of ten but I saw no point in that because it would use up our time. I think that was not the only way of doing our particular investigation but I did not study further into this issue so I do not know any details or facts. Yes I am positive that the results of our experiment are pretty reliable because our preliminary experiments and results show similar patterns. We could extend our investigation by researching other factors that could make our results more reliable but we were not given the time to do that in class where the equipment was.
