I will keep the time the same –4.20, so that each test will have the same amount of time to react and this will then show what effect different amounts of acid, water and the temperature will have.
I could make sure that the temperature is the same by using a water bath to insure that the temperature would be kept constant. The more kinetic energy means that the particles will move faster, and this means that there will be more collisions, and therefore a more successful reaction.
Also if I crushed the marble the surface area would be the same.
Method
For this experiment I will use the following equipment
Beaker x2
Teat tube
Timer
Water
Marble
Hydrochloric acid
What I will do
Measure out the marble chips and put in to the test tube, measure out the hydrochloric acid in a beaker, add the measured water in with the beaker. Pour the diluted acid over the marble chips and put the stopper on (connect to delivery tube). Start the timer and at the end of the time record the volume of gas released.
My predictions
I predict that the more concentrated acid that is added to the marble will have the greatest effect on the reaction rate. By increasing the amount of water to the acid solution, the weaker it will be and so this will produce less of a reaction.
Also as my work on the collision theory show the more surface area there is then the more collisions and the better the reaction could be, and if I was to increase the temperature this would cause more energy and produce more collisions.
Results table
This is my table of results I have shown the two lots of experiments that I have done. (the second in pink)
My results show that the more acid that is added and the less water will make the reaction faster as the table shows. With 1.07g of marble and ocm3 of water produces the most volume of gas. The more dilute the solution would create a much slower reaction with the least gas produced.
To increase the surface area would make more collisions and so the reaction would be faster. The more surfaces there are will show a quicker reaction and so there is more gas evolved.
Calcium carbonate + hydrochloric acid -> calcium chloride -> carbon dioxide + water
Caco3 + 2hcl -> cacl2 + co2 + h20
Averages
These are the averages that I worked out using both of my results. I have proved my predictions right.
Evaluation
I have proved that my predictions were right, as the experiment showed that by adding a greater amount of acid to water there would be much more energy and so more collisions and a better faster reaction. My graph shows that there is a straight line, I can use the gradient of the line to show where the reaction rate is best. This shows a positive correlation and proves that my method is right. So I can prove that the higher the concentration the higher the reaction rate.
To improve the accuracy of this experiment I could use a water bath to keep the temperature constant could also use a more accurate measuring method such as a burette. The marble could be crushed this would also allow more surface area and would be more the same size.
Conclusion
To conclude to my experiment I will show my results and what I have found.
I have found out that as my evaluation says the more acid added to less water will create a more reactive reaction rate and more gas will be produced as a result of this.
This is why when there is less acid and, more water there is less gas produced because the reaction rate had less energy and so there were less collisions and so an slower reaction so less gas would be produced.
