How the concentration of an acid affects the rate of reaction on marble chips :: GCSE Chemistry Coursework Investigation

How the concentration of an acid affects the rate of reaction on marble chips Background: These different speeds of reaction are referred to as their rates. The rate of reaction depends on how often and how hard the reacting particles collide with each other. Particles have to collide in order to react, and the have to collide hard enough as well. This is called the collision theory. When the temperature is increased the particles all move quicker. If they are moving quicker then they are going to have more collisions. Reactions only happen if the particles collide with enough energy. At a higher temperature there will be more particles colliding with enough energy to make the reaction happen. This initial energy is known as the activation energy, and it is needed to break the initial bonds. If one of the reactants is a solid then breaking it up into smaller pieces will increase its surface area. This means the particles around it in the solution will have more area to work on so there will be more useful collisions. A catalyst works by giving the reacting particles something to stick to where they can bump into each other. This obviously increases the number of collisions too. If the solution is made more concentrated it means that there are more particles of reactant knocking about between the water molecules, which makes collisions between the important particles more likely. Chemists overseeing large reactions in industrial situations must carefully consider the rates of reactions. For some reactions, such as the production of a final material, fast reactions will be desirable to increase production and therefore sales profit. For other reactions, such as the degradation of a material, reducing the rate may be beneficial to increase the lifetime of a product. Times Education Series Chemistry GCSE Plan: I will investigate how the concentration affects the rate of reaction between hydrochloric acid and calcium carbonate (marble chips). The rate of reaction can be measured by measuring the amount of gas produced after a certain amount of time. The reaction will take place in the conical flask from where the gas produced will travel into the up-turned measuring cylinder. The gas will then displace the water in the tube. I will measure out exactly 50ml of 1molar hydrochloric acid into the conical flask. I will then weigh out exactly or as close as possible to 2 grams of small sized marble chips. I will put the chips into the flask with the acid and immediately place the bung over it so as to lose as little gas as possible. I will then take readings at intervals of fifteen seconds.