An experiment to investigate whether concentration of acid has an :: GCSE Chemistry Coursework Investigation

An experiment to investigate whether concentration of acid has an effect on the reaction rate of the reaction between Calcium Carbonate and Hydrochloric Acid. 1. The key factor I plan to investigate and what I will do to make my experiment a fair test The factor that I plan to investigate is whether the concentration of acid (the acid being HCl) has any effect on the rate of reaction between Calcium carbonate and Hydrochloric acid. I will vary the concentration and calculate rate of reaction, and calculate the effect of the factor by measuring the amount of gas given of during the reaction, and finding out how much gas is given of every 15 seconds. I will collect the gas by bubbling it into a gas collection tube in a water bath. I will use five different concentrations 80%, 70%, 60%, 50%, and 40% acid. I will mix acid with water to get the desired concentration, and for each experiment I will keep the volume of the acid and water combined at 50 ml. For example in order to 80% concentration I will mix 40 ml of acid, and 10 ml of water. For each different concentration I will conduct 3 identical experiments, and collect my results every 15 seconds. I will then average out the three different results for one particular time and produce one result. I will collect 8 results per an experiment. I will repeat any measurements that don't appear to follow the general trend. Also to make sure that results are accurate I will use a 100 ml measuring tube with marking for every 1 cm3. I will measure the liquid in a test tube with 1 cm3 marking. I will conduct my experiment in the laboratory. The equation for this experiment is: CaCo3 + 2HCL CaCL2 + H2O + CO2 The variables I plan to control 1. Surface area: The surface area of each marble chip should be kept relatively the same because due to collision theory if more surface area is available the number of particles of solid reactant available for collision will increase. Therefore more collisions can occur, and it is likely there will be more collisions with sufficient energy to successfully lead to a reaction. I might not be able to keep the surface area of my marble chips exactly the same but I will attempt to keep it as similar as possible. 2.Volume of liquid: I will keep the amount of liquid at 50 ml, because if I don't keep the amount of liquid constant I will change the amount of acid in contact with the marble chips, because if there is more HCL