Rates of Reaction
Aim : We did 4 experiments to find out how the rate of reaction changes with differing concentrations of Sodium Thiosulphate, Hydrochloric Acid and water. ... Sodium Thio-sulphate (cm3) Water (cm3) Hydrochloric Acid (cm3) Graph number 20 0 3 DPPAS_02 15 5 3 DPPAS_03 10 10 3 DPPAS_04 5 15 3 DPPAS_05 We did not do the experiment in which 0cm3 Sodium Thiosulphate and 20cm3 water were used, as there would have been no reaction. ... how long it took for the reaction to get to a certain point of cloudiness. It would not tell you the varying rates of the reaction. You would not be able to tell if the reaction speeded up, slowed down, went steady all the way e. ... Lastly, what would you do if the reaction never got as far as making the cross disappear? Or what if the reaction took a number of hours to get that far? ... Prediction : I predict that the rate of reaction will increase (and get more cloudy, more quickly) when the solution of Sodium Thiosulphate and Hydrochloric Acid are strongest, and there is no water. The reason for this is that it will be easier for the Sodium Thiosulphate to react with the Hydrochloric Acid, as they are the only two chemicals in the beaker, and there is not water to hinder the rate of the reaction. ... To work out the rate of reaction over the whole reaction (up to the point where the reaction levelled), I divided the light depreciation (k lux) by the time taken (minutes) to give a rate of k lux/min. Light depreciation is k lux at start minus k lux at end of reaction.