Rate of Reaction Coursework Essay -- GCSE Chemistry Coursework Investi

Investigate if changing the concentration of an acid will change the rate of the reaction when marble is dissolved in hydrochloric acid. Apparatus Marble Chips Conical Flask Hydrochloric Acid Gas Syringe Delivery Tube Stop Watch Fair Test To make the experiment a fair test I will use the same amount of acid for each concentration. I will do this by using a capillary tube because they are very accurate. I will use 3g of marble in each concentration of acid. I will clean everything out before I start the next experiment with a different experiment. Safety ====== Magnesium is flamable and when it reacts with acid an exothermic reaction takes place releasing a large amount of heat energy. Acids are corosive so saftey glasses must be worn. Method I will use Marble chips all of a small size. I have decided to use 3g or marble chips. The amount of acid I have decided on is 20ml. I will measure this by using a burette, a very thin tube that lets out the acid when you turn the tap; it gets very accurate amounts of acid. I can measure the speed of the reaction by how much gas is given off. I can measure this in cm3 in a gas syringe. When the experiment takes place, I will take the reading every 10 second to get a good graph for the results. If the reaction goes very quickly, I will take the readings every five seconds. I will use acid of 0.5, 1, 1.5, 2 and 2.5 molar concentrations. To be sure I can rely on my results I will repeat he experiment twice or three times if necessary, because there is chance of inaccurate results for many reasons. Calcium Carbonate + Hydrochloric acid Calcium Chloride + Water + Carbon Dioxide CaCO3 + 2HCl CaCl2 + H2O + CO2 Prediction ========== I predict that if the concentration of the Hydrochloric a... ...would have been a lot similar. If I did use Powder however, the concentration of acid may have had to be weakened as the reaction would have taken place a lot quicker due to the very large surface area and readings wouldn't have been as accurate. Secondly, an inaccuracy may have been caused by the fact that the temperature may have dropped during the reaction. This could have been used if I used a water bath to heat up the acid to a constant temperature. You have to allow for a margin of human error during the experiment, some people react slower than others and you have to rely on the person taking the readings with the stopwatch. The results were reliable because they were almost the same in both experiments, even though there was an anomalous result; it happened in both experiments, so the results were still relibale, I have no explination for the anomalous result.