- Every 10 seconds I measure the amount of CO in the test tube until finally reaching 90 seconds.
- This will enable you to find out how much CO is produced and how quickly it’s produced.
- Change the concentration of HCl to the next highest until finally reaching 1.5M.
- To make it a fair test, repeat each concentration experiment 3 times.
- For safety, use safety goggles because the acid being used is corrosive and therefore can damage your eyes.
Prediction
I predict that the lower the concentration of HCl used, the longer it will take for the test tube to fill with CO .The higher the concentration of HCl used, the test tube will fill faster as the HCl is reacting with the CaCo faster.
This is because the higher the concentration is, the more particles there are in it, so there is a higher chance of it reacting then it with a lower concentration. This is a great example of the collision theory.
The following equation will explain my prediction:
No. of Moles = Molarity x 10cm³
1000
Analysis
Concentration
From this investigation I found out that as the concentration of acid increases, the rate of the reaction also increased.
The rate of reaction followed a pattern in the other concentrations. The marble began to react quickly and gradually slowed down over a period of 10 to 40 seconds.
From my results, I can see that my prediction was correct because as I increased the concentration of acid, I was increasing the number of particals (also known as molarity). The collision theory suggests that when particles collide, they react. By calculating the molarity, we can work out how many particles there are and predict how likely it is a reaction will occur.
Surface Area
From this investigation I found out that a reaction is more likely to occur in the small pieces of marble as the surface area is greater than that of the large chip of marble.
The rate of reaction followed the same pattern as the concentration of acid experiment which was that it reacted quickly to begin with but gradually began to slow down.
Evaluation
After doing this experiment, I now understand the collision theory and how it works. It was of great help in my view.
I had only one unusual result which was the o.25m at 70 seconds. This may be incorrect because one of the three tests carried out may have been unfair.
I believe that the experiment was reliable because I carried out the test three times to make it fair and compared my results with others.
I could improve this experiment by seeing if distilled water would change my results instead of using tap water.
A relevant experiment that would work well with the one I have just carried out is the CO /Squeaky pop experiment, where you light a splint and place it inside a test tube of unknown gas. If it goes out its Co . If it makes a pop sound, it is hydrogen.
Another experiment which is relevant is the temperature testing of the marble in hydrochloric acid. The point of this is to see if the temperature of the acid affects the rate of reaction.
Number of Moles in Each Concentration
0.25m = 0.0025M
No. of moles in a solution = Molarity x 10mls (volume)
1000
=0.25m x 0.01
=0.0025M
0.50m = 0.005M
No. of moles in a solution = Molarity x 10mls (volume)
1000
=0.50m x 0.01
=0.005M
1.00m = 0.01M
No. of moles in a solution = Molarity x 10mls (volume)
1000
=1.00m x 0.01
=0.01M
1.50m = 0.015
No. of moles in a solution = Molarity x 10mls (volume)
1000
=1.50m x 0.01
=0.015M
