Different people watching when the ‘X’ disappeared meant that there are more likely to be errors and could make our results less reliable.
Our results show a clear patter – as the concentration of sodium thiosulphate increased, the time taken for the ‘X’ to disappear decreased; this proves the collision theory.
Introduction My investigation is about the rate of reaction.
A rate of reaction is defined as how fast or slow a reaction takes place.
Measure volumes of sodium thiosulphate and water using results table Add 3ml of HCL into the flask.
Dissertation Proposals Examples - Chemistry Coursework Sodium Thiosulphate Concentration
Immediately time how long it took until the ‘X’ was no longer visible, how long it took for the solution to turn cloudy The person observing when the ‘X’ disappeared then recorded the time.Digital Stopclock – Used to time how long it took for the solution to turn cloudy and it’s a more precise reading than an analogue clock (mili seconds). Paper marked with ‘X’ – Used to see whether the solution is cloudy enough to make the ‘X’ not visible.Two Beakers – To hold acid and sodium thiosulphate in while we carried out the experiment.Use of Catalyst – If a catalyst is present then the reaction rate will increase due to the fact it replaces the amount of energy needed for the collision, allowing for more collisions to take place.Aim: We will be investigating the rates of reaction when we will mix together sodium thiosulphate and hydrochloric acid.When temperature is increased the particles move faster and with more energy, therefore the collisions happen more often and with more force so the reaction is faster.Four Factors which affect Rates of Reaction: Surface Area - Surface area is the measure of how much exposed area a solid object has, expressed in square units.Three Measuring Cylinders (two 10ml)(one 25ml) – Each used to accurately measure how much sodium thiosulphate, water and acid are used in the experiment.Pipette – Used to put small amounts of acid into a measuring cylinder because it holds small amounts of acid in it so I can receive an accurate measurement.Temperature - Heating chemical substances can make the molecules separate and move around faster.This can increase the speed with which they mix with surrounding molecules from other chemical substances, thus speeding up a reaction.