Disappearing X Experiment. Coursework about sodium thiosulphate and hydrochloric acid. Method, Results, Fair Testing, Evaluation included. Was marked with a passing grade.

Disappearing X Experiment Introduction I am going to investigate the rate of reaction between sodium thiosulphate (thio) and hydrochloric acid. Hydrochloric Acid + Sodium Thiosulphate "" sodium chloride + water + sulphur The reactants are both colourless, but one of the products, sulphur, is yellow, so we can use this fact to follow the rates of reaction. I am going to investigate how the concentration of the acid effects the speed of the reaction. Apparatus 1 small measuring cylinder 1 large …

…a faster reaction. If the solution is diluted, there aren't as many acid particles to collide with the thio particles and so the reaction is much slower. Results /mins Acid/cm3Water/cm3Reaction Time 1Reaction Time 2Average Reaction Time 2501.522.332.12 2052.092.432.26 15102.242.542.39 10153.053.383.21 5204.585.555.26 /secs Acid/cm3Water/cm3Reaction Time 1Reaction Time 2Average Reaction Time 250112153132.5 205129163146 1510144174159 1015185218201.5 520298355326.5 Analysis/Conclusion We discovered that 25cm3 hydrochloric acid and 25cm3 sodium thiosulphate solution had the fastest reaction rate, just as we had predicted.