How changing the concentration changes the rate of reaction. :: GCSE Chemistry Coursework Investigation

How changing the concentration changes the rate of reaction. Introduction We are going to look at the following factors during this investigation: 1 Why altering rate could be an advantage 2 Good ideas to control the rate of reactions 3 Briefly mention the factors that can change the rate of reaction such as: - Temperature Surface Area Catalyst Concentration I am going to find out if changing the concentration of nitric acid in water and see if it has any effect on changing the rate of which precipitate is formed when reacts with sodium thiosulphate. Prediction I think that a faster reaction will happen with a higher acid concentration as there will be more successful collisions with sodium thiosulphate, which will result in a faster reaction because the product will be produced quicker. Apparatus 1 Conical Flask 2 Beakers 3 Measuring Cylinders Paper with a black cross on Stopwatch Nitric Acid Sodium Thiosulphate Water Safety Glasses Method For my experiment I will measure out 25cm ³ of Sodium Thiosulphate and put it in a conical flask. I will put the flask on top of a piece of paper that has a black cross drawn on it. I will then measure 15cm ³ of Nitric Acid and add this to the Sodium Thiosulphate in the conical flask. The two should react together to make a cloudy precipitate and we are going to time how long it takes for the liquid to turn cloudy until we can’t see the cross underneath the glass anymore. We are going to carry this experiment out a number of times but each time we will decrease the volume of Nitric Acid by 1cm ³ and add 1cm ³ of water. Each time we will decrease the Nitric Acid and increase the volume of water to see which one holds the fastest reaction. Our final amount of Nitric Acid should be 5cm ³ and 10cm ³ of water. I will repeat the experiment 3 times to make sure that my results are as accurate as they can be. I will then record my results onto a graph so I can compare them better and make a line of best-fit graph to show my results even clearly. How will I make it a fair test? To make sure that my experiment is fair I will always use the same amount of Sodium Thiosulphate and the only factor I will change will be the volume of Nitric Acid and water but only to total 15cm ³ so the depth of the liquid will always be the same. Also, I will always use the same conical flask and wash it out after every time I have used it. Evaluation First of all we put our safety goggles on, and then we added 25cm3 of