Apparatus
The apparatus which I will require for this experiment ….
- Conical Flask
- Delivery Tube
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Bung -To stop Carbon Dioxide from escaping and all of the gas can be measured in measuring cylinder
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Stop Watch - To time reaction for 2 minutes then measure CO2
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Electronic Balance - To weigh marble chips at 0.5g accurately
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Beaker - For reaction to take place in.
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Marble Chips (Calcium Carbonate CaCO³) –To react with Hydrochloric Acid and to measure amount of gas collected after two minutes.
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Hydrochloric Acid -At different concentrations, to add it to Calcium Carbonate Marble chips and measure amount of gas collected at different concentrations.
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Measuring Cylinder -To measure volume of Carbon Dioxide collected when Hydrochloric Acid reacts with Calcium Carbonate
Method
To measure different concentrations of Hydrochloric Acid firstly we will need 2M Hydrochloric Acid and we need to measure the Hydrochloric Acid at 20cm³.
Secondly we will add 15cm³ of 2M Hydrochloric Acid and 5cm³ water measured using a measuring cylinder, by doing this we have 1.5M Hydrochloric Acid.
Thirdly we will add 10cm³Hydrochloric Acid and 10cm³water into a beaker, so we have 1.0M Hydrochloric Acid and we will use the same method as before to get 0.5M Hydrochloric Acid and 2.5M Hydrochloric Acid.
We will begin to time when the marble chips are added to the acid, and we will stop timing after two minutes and we will measure the volume of gas collected in the measuring cylinder.
To keep it a fair test we are going to keep the weight of the marble chips regular in this investigation the marble chips will be weighed at 0.5g and the concentration of Hydrochloric Acid will be changed and each concentration experiment will be repeated three times giving us an average in total and to keep it a fair test.
The step by step method we will be using is…..
- Connect the bung, the delivery tube and gas syringe.
- Measure the weight of the marble chips using the electronic balance weigh each set at 0.5g
- Put 2M Hydrochloric Acid into a Conical Flask and then add marble chips, use the bung to cover the top of the conical flask, so the amount of gas collected can be measured.
- Set the stop clock so it counts down two minutes, after two minutes stop the clock and read how much gas has been collected and record the data.
- Use the same method for concentrations of 2.5, 2, 1.5, 1, and 0.5M Hydrochloric Acid
When using these chemicals we need to be careful when handling harmful substances such as Hydrochloric Acid, If any Hydrochloric Acid is made in contact with any part of the body immediately wash that part thoroughly and take other precautions such as wear goggles. Wear rubber gloves and wear safety lab coats and try not to spill chemicals and be careful with apparatus.
Diagram
Graph Expected
Graph Expected
Results
When we were doing this experiment we decided to alter our method, by only using four different concentrations we thought they would not be enough so we decided to add another concentration of Hydrochloric Acid which is 2.5M.
Analysis/ Conclusion
(Graph is On Graph Paper)
Looking at my results I feel that the prediction I made before carrying out the investigation was correct. From these experiments we learnt that as the concentration of Hydrochloric Acid increased when reacting with Calcium Carbonate (CaCO³) marble chips the volume of Carbon Dioxide gas given off increased, this is because increasing the concentration of any reactants will increase the frequency of successful collisions and more particles will collide and therefore this will cause the volume of products being formed to be increased and the volume of Carbon Dioxide to be increased.
The graph which I drew after collecting my results was similar to my predicted graph but in the last three experiments when the concentration of Hydrochloric Acid was 2.5M the amount of Carbon Dioxide gas given of was higher then I expected, this surprised me because when the concentration of Hydrochloric Acid was 2M the volume of Carbon Dioxide gas collected during the reaction of Hydrochloric Acid (HCl) and Calcium Carbonate (CaCO³) marble chips the average volume of Carbon Dioxide collected was 20.3cm³ where as when the concentration of Hydrochloric Acid was 2.5M the amount of gas collected was 40.3cm³ which had doubled.
Looking at my results there is a trend in the results which is as the concentration of Hydrochloric Acid increases the volume of gas given off increases.
Overall my conclusion supports my prediction and my predicted graph is very similar to my final graph and my prediction was supported by my results, that is in any chemical reaction as the concentration of any of the reactants increases the rate of reaction increases, in this case it has been proven that as the concentration of Hydrochloric Acid increases when reacting with Calcium Carbonate (CaCO³) the amount of gas given of which is Carbon Dioxide increases.
Evaluation
In this experiment the variable which we decided to change was the concentration of Hydrochloric Acid and we were going to investigate whether concentration of Hydrochloric Acid affects the amount of gas produced when it reacts with Calcium Carbonate marble chips. Looking at my results it can clearly be seen that as the concentration increases the amount of gas produced increases.
I think that the procedure I carried out was also very good because the experiment was setup in a simple way and the results we achieved were also good.
My results in my opinion were also good and this can be shown on my graph and there was also a trend in these results, I think that my results were of a good quality and I don’t think there were any problems with my results but when the concentration of Hydrochloric Acid was 2.5M the average volume of gas collected was 40.3cm³this was a bit higher then I expected, there are a number of reasons this could have happened for example the concentration of Hydrochloric Acid may have been a bit more then 2.5M or maybe the weight of Calcium Carbonate marble chips may have been a bit more then 0.5g or maybe we may have read the volume of gas collected incorrectly. There are a number of reasons why this result may vary slightly from the other results.
I feel that this investigation is completely valid because everything was carefully planned and I feel that the experiments carried out were also fair and we tried to keep everything as fair as possible for example we made sure that the stopwatch stopped at exactly two minutes and other precautions such as making sure the Calcium Carbonate Marble chip were weighed at exact 0.5g and not above or less then 0.5g and also by repeating experiments three times to make sure that the results we collect are reasonable. So I think that overall the experiment was fair because we did our best to keep it a fair test.
I feel that I have collected enough information and my results support my conclusion because I feel that the experiments I carried out were reasonably accurate and fair. I feel that I have collected enough result to support my conclusion this is because I changed the concentration of Hydrochloric Acid five times and repeated each concentration three times. I think that I have enough evidence to support my conclusion but I could develop my investigation by increasing concentration of Hydrochloric Acid to a higher concentration for example 3M/ 2M.
I don’t feel that I had any difficulties when I carried out these experiments, I only had slight problems when we had to weigh the marble chips at 0.5g because we had to fiddle with the marble chips to get them to exactly 0.5g because they had to be broken down to get the weight to 0.5g.
If I was to make any changes and to repeat the experiment I would change the concentration of Hydrochloric Acid to a higher concentration to make sure that my results would be even more accurate and fair. This would help because we would have a variety of concentrations so we would have a wider range of results to analyse and conclude on. This would make us more certain of our conclusion because we would have a wider range of results and therefore would be able to support our conclusion by the results produced.
So overall I am pleased with the results that I achieved and I feel that my prediction that as the concentration of Hydrochloric Acid increases when reacting with Calcium Carbonate Marble chips, the higher the amount of Carbon Dioxide produced and this can be proven by the experiments which I carried out.