Hydrochloric acid Essay Example for Free

Hydrochloric acid Essay Prediction I predict that the more marble chips there are, the faster the rate of reaction, because there is more marble for the hydrochloric acid to react with, I predict this because in previous experiments when working with the same equipment I found that if you put a lot of marble in the acid, the levels of water in the burette go down very quickly, compared to when you only put a little bit of marble in the acid and the levels of water go down much slower. I also predict that the hotter the temperature of acid, the faster the rate of reaction, because heat often works as a catalyst in experiments with acid. Increasing the temperature of the acid will increase the rate of reaction because particles move faster and collide more vigourously at higher temperatures. Plan I will fill a burette with water, and then turn it upside down in a beaker full of water. I will then put a tube into the bottom of the burette and attach it to another beaker using a bung to stop any air from leaking. I will then calculate the rate of reaction between the marble chips and hydrochloric acid by measuring how much the levels of water in cmi drops every 10seconds. So that it is a fair investigation I will make sure that I always start with 50cmi of water in the burette, and 1000cmi of acid in the beaker. I will also make sure that I take readings every 10 seconds, because otherwise my results would be invalid, or have results missing. The factors that I will investigate to see if they cause change are temperature of the acid, and amount in weight of marble chips. I will test 0. 5g and 1g of marble chips at every temperature, and will try and repeat every experiment twice so that I will be able to see whether any results seem totally inaccurate. I will test the rate of reaction at three temperatures, firstly I will cool the acid to 6i C. I will do this by putting the beaker of acid in a larger beaker of water and ice. This will ensure that no ice comes into contact with the acid so the water wont dilute it. I will then add the marble chips. I will then test the rate of reaction at room temperature, and after that I will test the rate of reaction at 55i C by heating the acid with a Bunsen burner and then adding the marble. I will set up the apparatus as below: Results: The rate of reaction for 0. 5g marble chips at 6 degrees C. Time (seconds) Level of water in burette (cmi ) 0 50 10 49. 4 20 49. 4 30 49. 4 40 48. 5 50 47. 6 60 46. 3 70 44. 1 80 43. 4 90 42 100 41 110 39. 9 120 38. 8 130 37. 6 140 36. 5 150 35. 8 160 34. 9 170 33. The rate of reaction for 0. 5g marble chips at room temperature. Time (seconds) Level of water in burette (cmi ) The rate of reaction for 1g marble chips at room temperature. Time (seconds) Level of water in burette (cmi ) The rate of reaction for 0. 5g marble chips at 55 degrees C. Time (seconds) Level of water in burette (cmi ) The rate of reaction for 1g of marble chips at 55 degrees C. Time (seconds) Level of water in burette (cmi ) 0Conclusion I conclude that my predictions that the hotter the acid, the faster the rate of reaction, because the particles move faster and collide more at higher temperatures, and the more marble chips there are, the faster the rate of reaction, because there is more marble for the acid to react with to be true. I can prove this because using my line of best fit on the averages graphs, I calculated the rate (by using the formula: Level of water/ Time (seconds)), at about 60 seconds in all but the hot acid experiments, where I worked out the rate at 40 seconds. I chose these times because at about these times the experiment was well underway, so the rate would be accurate, and it wouldnt be too late that the reaction was slowing down. I worked out that the rates were: Evaluation I think that the experiment went quite well overall, and we got some quite good results. I think if I did it again I would work with a weight of crushed marble chips instead of just a set weight of random sized marble chips, because the larger the surface area of something, the shorter length of time it takes to dissolve, and this could have effected the results of these experiments because the reactions that took longer may have taken longer because the marble was smaller in surface area than in other experiments. This is because the larger the surface area, the more particles that are in contact with the acid at any one time, so it will be able to react faster. I might also use different strengths of acid to see whether the stronger the acid is, the faster the rate of reaction. A stronger concentration of acid will increase the rate of reaction, because more collisions of molecules are possible in the same amount of time, because there are more particles available in the same volume of acid.