Investigate the factors, which affects how quickly Calcium carbonate reacts with hydrochloric acid.
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Investigate the factors, which affects how quickly Calcium carbonate reacts with hydrochloric acid. Rate of Reactions Aim The aim of this experiment is to find out how different variables affect the rate at which the reaction between Marble chips (CaCO3) and Hydrochloric acid (HCl) takes place. There are many variables that affect the rate of this reaction such as the following: 1. Temperature 2. Concentration 3. Surface area In my investigation I will be testing how changing the concentration of the Hydrochloric acid, the surface area of the marble chips and the temperature have an effect on the speed of the reaction. I will do various experiments and then evaluate the results and come to a conclusion. The reaction that will take place is CaCO3 + 2HCL = CaCl2 + H2O +CO2 Hydrochloric acid + Calcium Carbonate =Calcium Chloride + Water + Carbon dioxide Prediction My plan is to investigate three factors that could affect the rates of reaction. These factors are - Surface Area of calcium carbonate, Temperature of the water in the flask of hydrochloric acid is placed and the concentration of the hydrochloric acid. In the surface area experiment I predict that I change (increase) the surface area of calcium carbonate, the reaction rates will increase, e.g. Larger the surface area the faster it will react with acid. My plan is to use large lumps of calcium carbonate, small lumps of calcium carbonate and powered calcium carbonate. I also predict that by doubling the surface area you will double the reaction rates. If you use powered calcium carbonates, I predict the amount of gas collected after about 60 seconds would be 100cm, whereas if you use large lumps the amount of gas collected after 60 seconds would be about 30cm. The next factor I am investigating is temperature. I plan to use different temperatures (about 5). I predict that if I increase the temperature of the water I will increase the reaction rate.
to 50 degrees Celsius. * I placed 20ml of acid in the conical flask and put it in the heater water. I measured out 2 grams of calcium carbonate and put it in the acid and then closed it with a cork, soon I connected the tube, which leads to the acid into the water and under the Measuring cylinder. * then I wrote down my results and repeated the same step but changed the temperature of the water each time to 60 , 70 , 80, and the last one to 90 degrees Celsius. Method of Temperature * Set up equipment as shown in fig 4 * I made up four different solutions of acid to test concentration * First I test 2mole of pure acid. * I weight out 2 grams of calcium carbonate and placed it inside the acid. * Then closed it with a cork, soon I connected the tube which leads to the acid into the water and under the Measuring cylinder. * I then recorded the gas collected at intervals of 30 seconds. * I repeated those steps with the following mixtures of water and acid. Results Particles Size Large Lumps Time Taken-Seconds (s) Volume of CO2 Collected 1st Volume of CO2 Collected 2nd Volume of CO2 Collected 3rd Average (ml) 0 0 0 0 0 30 30 31 32 32 60 41 40 39 40 90 52 51 50 51 120 64 65 63 64 150 69 70 71 70 180 70 71 70 70 210 75 73 74 74 240 79 81 80 80 Small Lumps Time Taken-Seconds Volume of CO2 Collected 1st Volume of CO2 Collected 2nd Volume of CO2 Collected 3rd Average (ml) 0 0 0 0 0 30 59 60 59 59 60 70 70 71 70 90 85 84 83 84 120 99 98 97 98 150 100 100 100 100 180 100 100 100 100 210 100 100 100 100 240 100 100 100 100 Powered Calcium Carbonate Time Taken-Seconds (s)
the results that were derived from the experiments showed a pattern but the prediction that was made was not completely supported because the reaction rate did not shown any signs of slowing down. There was one anomaly, however, but this experiment was repeated to give results that matched the pattern. It is not certain why this result was found but it was probably due to the mass of the marble chips being measured slightly inaccurately because we measured the mass of the chips to the nearest whole number this would account for a slight margin of error. Another possibility is because the surface was different for each chip the total surface area was different this would be very unlikely, however. The measurements were accurate to about cm³ because this how often the cylinders were marked. The method did show the relationship between the concentration and the rate of reaction but there was a slight margin of error because when turning the cylinder upside down a small volume of water was lost. To solve this problem we could use a gas syringe but the problem with this is we could not test the higher volumes of gas, which would mean the range of results would be lower which would mean the pattern we got would be less obvious. The experiments were fair tests to a certain extent but there was a certain margin of error because the results recorded were only to the nearest cm³ and the values of the controlled variables were not exact amounts so the may have been slightly differently each time which would have affected slightly the reliability of the results. This would have made little difference to the results though as the volume of gas was only measured to the nearest cm³. It was also not certain if the concentration keeps increasing the rate of reaction or this only happens to a certain extent. This could be found out by extending the range of concentrations reacted. These reactions would have to conducted very carefully though as hydrochloric acid of this concentration can be very dangerous.
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