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Introduction

Chemistry Investigation - Rates Of Reactions. Aim: To use rates of reactions and kinetic theory to change the rate of a chemical reaction. Reaction: Calcium Carbonate + Hydrochloric Acid CaCO3 + HCl Plan: During my experiments I will be reacting Calcium Carbonate with Hydrochloric acid. I plan to undertake three separate experiments; in each one proving the kinetic theory. * Experiment 1 - I will change the temperature of the acid. * Experiment 2 - I will change the concentration (strength) of the acid. * Experiment 3 - I will change the particle size of the Calcium Carbonate. The following is a list of all the variables I could realistically change: * The type of acid. * The volume of acid. * The temperature of the acid. * The mass of calcium carbonate. * The molecule size of calcium carbonate. The variables that I will be changing during my experiments are the temperature of the acid, the concentration of the acid and the molecule size of the Calcium Carbonate. For each different measurement I will take three readings, to gain an average reading to make my results more accurate. During these experiments I will need: * A Bunsen burner - to heat the acid. * A Beaker - to hold the acid and for the reaction to take place. * Scales - to weigh the correct mass of the Calcium Carbonate. * Tripod and Gauze - to hold the beaker above the Bunsen burner. ...read more.

Middle

Method 2: For our second experiment, we carefully measured 40ml of water, using a measuring cylinder, and added the 0.5g of calcium carbonate (chalk). We then proceeded to time the reaction length. For the next measurement, we measured out 10ml of hydrochloric acid and added to it 30ml of water, to make 40ml of very dilute acid, we again added the 0.5g of chalk and timed the reaction using a stopwatch. We then continued with this process, increasing the volume of acid by 10ml and reducing the volume of water by 10ml and timing the reaction with the chalk, until we ended up with 40ml of pure Hydrochloric acid. The acid was always at room temperature to maintain a fair test. Again we repeated each experiment three times and used averages to gain more accurate and truthful results. Method 3: For the third experiment, we again carefully measured out 40ml of Hydrochloric acid using a measuring cylinder and cautiously poured it into a conical flask. Then we added 0.5g of calcium carbonate, which was carefully weighted on electronic scales in the form of chalk. We added the chalk to the acid and recorded how long the reaction took using a stopwatch. We then did the exact same thing, but this time measured out 0.5g of calcium carbonate in it sedimentary rock form of limestone, instead of chalk. The time of the reaction was again recorded using a stopwatch. Then we the exact same thing but instead used 0.5g of marble, which is the metamorphic rock form of calcium carbonate, instead of limestone. ...read more.

Conclusion

Not all collisions cause a reaction, only the ones which reach the activation energy of the reaction. This is why I predict that the rate of reaction will increase as the concentration of a solution increases. Activation Energy Activation Energy is an amount of Energy needed for a reaction to occur, this amount varies from different elements and types of reaction. This may save energy for industrial use, as they will only supply the exact amount of energy needed and not more. Evaluation: I feel that after completing my investigation I achieved everything I set out to do. I believe that each of the experiments were completed well because I identified the three factors that affect the rates of reactions like a proposed to do in my aim and plan. The only inaccuracies I can think of when doing the experiments is not achieving the target temperatures of the acids exactly, this would only have a tiny affect on the reliability of my results and the use of averages would have cancelled these out. If I had the chance to continue the investigation I would try and use more complex equipment and look at the affect of catalysts in a reaction. A catalyst is something that can greatly increase the rate of a reaction and is used a lot in industry to save companies time and money. All in all the investigation was completed with results to prove my predictions to be correct, and I feel that my results are very accurate and reliable. Every effort was made to keep all of the tests fair and honest and I am very pleased with my outcome. 1 ...read more.

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