How the change of Hydrochloric Acid concentration affects the rate of reaction with Marble Chips :: GCSE Chemistry Coursework Investigation

How the change of Hydrochloric Acid concentration affects the rate of reaction with Marble Chips Aim To find if changing the concentration of an acid will increase or decrease the rate of the reaction when marble is dissolved in hydrochloric acid. With the equation CaCO3 + 2HCl CaCl2 +H2O + CO2. The rate of the reaction affects how quickly the CO2 is produced. Background Knowledge ==================== 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. Higher temperature also increases the energy of the collisions, because it makes all the particles move faster. Increasing the temperature only causes faster 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. If the solution is made more concentrated it means that there are more particles of reactant moving about between the water molecules which makes collisions between the important particles more likely. Because of this I expect the reaction rate to be quicker when the concentration of the acid is higher. The reaction should however, end on the same amount of gas given off. Rate is measured by the disappearance of reactants and/or the appearance of a product. Prediction When the concentration of acid increases the rate of reaction will increase. I will be able to see the rate of reaction is increasing as the gas is produced more quickly. Equipment ========= Clamp Stand Hydrochloric Acid Medium Marble Chips Measuring Cylinder (100ml) x 2 (clearly mark each for water or acid) 250 ml conical flask Balance Gas Syringe Safety Equipment i.e. Lab coat, goggles Boiling Tubes Stopclock Delivery Tube Thermometer Method ====== * NB: before each experiment, ensure that the air temperature is consistent. * Using the measuring cylinder specific for the acid, measure out the specified amount of hydrochloric acid. Then, measure out the specified amount of water in the other measuring cylinder. Pour both of these liquids into a boiling tube.