I will set the apparatus out as shown above. To make it a fair experiment I will always add three marble chips and 10ml of acid to the test tube, for the first experiment. The clock will start with the test tube is secured with the bung. I will count how many bubbles come out in a minute. I will also check at certain intervals how far the bubbles of CO2 have reached in the burette (cm3). For the second experiment I will place 5 chips with roughly the same weight into separate test tube.
The different test tubes will have a different acidic strength (molar). When The marble chips and the acids are added together I will time how long it will take for the bubbles to stop. Prediction: I predict that as the concentration of the acid decrease, from the selection I have chosen, the time of the reaction will increase, as the acid will consume the marble chips slower. There would also be fewer bubbles, coming out of the delivery tube, which is connected to the boiling tube.
For the second experiment I predict that as the concentration of the acid increases the chips will be consumed quicker and the bubbles will disappear. Other experiments: Other ways in which I could have measured the rate of reaction was to use different weights of marble. For example I could have used only one marble chip or grinded a marble chip or I could have used 1-? amount of marble (as long a I had the resources). I could have measured how long it took the bubbles to fill up to reach 40, 30 20 etc. Results (1st): Concentration of acids (M)
Bubble Count (1st) Bubble Count(2nd) CO3 (5 seconds)(1st) 24 13min, 11sec Graph: From the results I have retrieved I will make two graphs to explain the experiment. I will use two line graphs to do this. (Look at graph paper). Analysis: From the results I have found and the tables that I have drawn I can tell that as the concentration of the acid, in molars, increases there are more frequent appearances of bubbles and the burette fills up with CO3 quicker. For the second experiment I have found that there is a pattern as in the first table all the lines seem to curve in practically the same way.
The graph allows me to measure the gradient accurately. From the table I can see that as the acid molecules were more stronger they worked quicker to consume the marble chips that had a quite a bit of surface area. From the results I found I believe that my prediction was correct. I said that as the acidic concentration increased the marble chips will be consumed quicker. From the two experiments that I did I believe that the rate of reaction experiment was more better than the other as it gave me more results. Conclusion:
From all the experiment that I have done, on the rate of the reaction and how long it takes certain acids to consume marble chips, I have concluded that my experiment was successful in the sense that all the measurements gathered were accurate and that they showed the needed result to make the tables. I think that the acidic concentration effects the marble chips in the first experiment. And in the second experiment I think that acidic concentration also effects the marble chips in this experiment as well. Evaluation:
From the results I have retrieved the quality of them depended on the accuracy of the instruments I used. These instruments included a burette to collect the CO3, a measuring cylinder to measure the liquids I was using and a clock to measure how long the experiment ran. The burette was only accurate to 1 millimetre so 1/10 of a centimetre. The measuring cylinder was only accurate to 1 millilitre. The clock was only accurate to 1 second so it was hard to interoperate where the pin exactly stopped, if it stopped in the middle of the second markers.
The top pan balance was only accurate to 2 decimal places and 0. 00g. The acids were in molars and as the results were retrieved on different days the concentration may have varied in this period. The marble chips weren’t weighed in the first experiment so they may have given an inaccurate result. The accuracy of the reading I took were hard to see as it was difficult to determine, whether the marble chip had dissolved in the acid. The clock sometimes didn’t start when the lever was moved upwards. Each reading that I took was repeated at least twice.
From these two readings I made an average conclusion to plot the graph. The only abnormal and uncommon result that I spotted was in the second graph. It was the point where the 3(M) mark was plotted, it was not supposed to be there. The good points about my method were that they were repeated enough times to make an average and hence eliminated any chance of there being a mistake. The bad points about my method were that the marble chips were not always the same weight. The solution of the acid was not measurable so you have to make an estimate the concentration of the acid.
As the results were taken on different days the temperature in the room may have varied through the duration of the experiments. I could have used a more effective clock to get better readings. I could have proceeded to use larger amounts or other concentrations of acids. Instead of the experiments that I did I could have done something different for example collecting the gas in a test tube and seeing whether or not it was flammable. Instead of having to repeatedly count the bubbles, which passed through the burette I could have used a laser to count the bubbles.