We are using 3 acids to check the how the sizes affect the rate in order to be able to support our conclusions and data analysis more. We are using 3 acids so our data collection and evaluation can be more precise, accurate and reliable. We are taking the Co2 given in 3MINS because we want to see the highest we know for sure that all the reaction will eventually react and end, but we are checking how much it has reacted over a specific constant period of time. This will enable us to find out our data.
Hypothesis:
I predict that the lesser the surface are of the marble chips are, the more Co2 will be collected and therefore the more the rate of reaction will be. I think this will happen because of one main reason. I believe this will happen because the reactor (the acid solution) will have more surface area to act upon. For example if the piece was bigger then the acid will only react with the outer part of the marble. But if the marble was powder for example then the acid would react with every surface and collusion will be more frequent of the marble and therefore the rate of reaction is increased.
Apparatus:
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Acids of 0.5 mole each (Hydrochloric acid, Nitric Acid and Sulphuric Acid)
- Syringe 70ml volume holder
- Measuring cylinder, 100 ml
- Calcium carbonate total area of 216 cm^2.( we need a total of 216 because we are going to use 12*3*3 plus 8*3*3 plus 4*3*3 (cm^2)
- Stop watch
- Straw flexible tube
- Flask
- Bung
- Tripod stand
Diagram:
Method:
- The first step to our experiment is to find the three types of marble chips. First of all the small chips, then the medium chips and finally the large ones.
- Then what we had to do to make the experiment a fair test was to make all the material the same weight since they all have to be the same volume because were only measuring the difference with surface area. Therefore we took it to the Digital balance and then we measured it to three grams.
- After that what we did was we took both types of acid (hydrochloric, and Nitric acid) and we measured out the amount we needed for every experiment which was 100ml.
- After that we took the big tray and filled it with enough water so that we can put in the measuring cylinder and the tube in together under the water.
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After that we took the clamp and hung the test tube from it and the measuring cylinder was upside down so that the opening was under water. Of course the measuring cylinder had to be filled with water in order for us to measure the amount of CO2.
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When the experiment was ready to be taken into progress what we left for the last step was to put in the marble chips because that was what was going to start the reaction that we wanted to see. Therefore what we did was put in the type of marble chips into the flask to start the reaction and then block it with the cork that has the tube attached to it that will take the CO2 into the measuring cylinder.
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After that we wait for exactly three minutes and take the tube out of the measuring cylinder so that it doesn’t transfer any more CO2 into the measuring cylinder for then it will not be a fair test. After we stopped the experiment we take down/record the amount of CO2 on the table’s we created.
Data Collection:
Solution: Hydrochloric Acid (0.5 moles)
Material: CaCO3
Measuring: Amount of CO2m
Time: 3 minutes
Average = sum of numbers/Number of Numbers.
Average for the first testing (12cm^2) = 15 +15+16= 46/3
Average for second testing (8cm^2) =23+24+24=71/3
Average for third testing (4cm^2) = 59 + 60+60 = 179/3
Solution: Nitric Acid (0.5 moles)
Material: CaCO3
Measuring: Amount of CO2
Time: 3 minutes
Average = sum of numbers/Number of Numbers.
Average for the first testing (12cm^2) = 12+13+12= 37/3= 12.7
Average for second testing (8cm^2) = 20 +21+20= 61/3=20.667
Average for third testing (4cm^2) = 51+52+53 =158/3= 52
Solution: Sulphuric Acid (0.5 moles)
Material: CaCO3
Measuring: Amount of CO2
Time: 3 minutes
Average = sum of numbers/Number of Numbers.
Average for the first testing (12cm^2) = 2 +2 +3=7/3=2.667
Average for second testing (8cm^2) =5+6+5= 16/3=5.667
Average for third testing (4cm^2) = 8+8+9 = 25/3=8.667
Data Processing and analysis:
Table sowing the relationship between the Surface area of the calcium carbonates and the amount of Co2 Produced by the different Acids
Graph:
Graph showing the ralationship between Area of marble chips and Amount of Co2 for Hydrochloric Acid
For Sulphuric Acid:
For Nitric Acid:
Looking at the shape of the graphs we can tell that there is a negative correlation in all the three different lines. This means that as the x axis is decreasing the Y axis value is increasing this shows us that as the size of marbles are decreasing the reaction is increased.
This graph also explains that all the acids react in the same way and therefore this strongly suggests that as the area of the marble decreased the reaction increased.
Conclusion:
The Data analyzing unit above clearly shows the relationship between the areas of the calcium carbonate chips and the amount of Co2 produced. It shows that as the area in the x-axis drops the Co2 amounts in the y-axis increases. Therefore as the marble chips get smaller the reaction went faster over a specific amount of time. For example when the area dropped from 8-4 in the hydrochloric acids line we see that the CO2 produced sky-rocketed by 40 ml of Co2. This strongly proves my hypothesis right. After noticing how the 3 acids behave in the same way we see that even though hydrochloric acid naturally reacts more with calcium carbonate than the other 2, that they all act in the same way. This makes the graph more reliable as we see that they behave in the same exact way and they have the same correlation. This also supports my hypothesis earlier that all the acids when reacted with the smaller chunks of calcium carbonate over time will have more reaction. The values and conclusions I have drawn is not surprising knowing the collusion theory. The collusion theory states that in a reaction, as the reaction is taking place atoms are colliding with each other, so if the marble chips are smaller than it has more parts and atoms colliding in a shorter period of time.
Evaluation:
The lab results were repeatable and formed a consistent trend throughout the 3 trials and 3 tested variables. Therefore the results will appear to be reliable and valid with no outlying results. However there were possible sources of error in the data collection unit in this experiment as in all experiments.
- More Trials. We only used 3 trials to get an average. If we used more trials for example 5 trials it would give us a more accurate and a more reliable data. Using more trials will help give specificity to our Data Analysis. For example we only have 3 points in the graph for each line. If we had for example 5 or 6 tested variables this will help strengthen the proposition of the graph.
- We did not test a wide variety of acids. As we know the acids react differently. If we tested, for example 8 acids we can make a more general statement. We never know if it is only these specific acids this size theory works for, always, testing more variables will help make a better general statement.
- Other factors that affect the rates of reaction might have biased the data analysis a bit. For example the temperature of the marble chips or the acids used might have differed and since temperature affects the rate of reaction, the data might have been corrupted. Since we are checking for the rates of reaction this issue is a really huge problem that can lead to huge inaccuracies, but that is only if the temperatures differed by a lot. I mentioned this in my controlled data section. The major thing is that we cannot make the temperature within the marbles the same. Since marbles are heat convectors it is really hard to keep temperature in this experiment constant.
