The determination of a rate equation Assessed Practical
]Aim
To investigate the rate equation of
Apparatus
burettes
Pipettes
Conical flask
Distilled water
0.4 mol dmsodium thiosulphate
2.0 mol dm Hydrochloric acid
paper
Stop clock
Diagram
Method
To determine the order of reaction of each reactant , I will keep one reactant in excess while changing the concentration of the other . I will place a conical flask on top of a sheet of white paper with a black cross of ink in the centre . The reactants will then be added to the flask ( see table below ). A total of 70 cm of reactants will be used each time (50 cm of Sodium thiosulphate and 20 cm of HCl ) , this will keep the depth of the solution the same each time so that the optical properties of the liquid to not change . Using a burette to make up the desired concentration of sodium thiosulphate diluting with distilled water if required , pipette 50 cm into a conical flask . Pipette 20 cm of HCl into a test tube , pour the contents of the test tube into the conical flask . When the last of the HCl enters the flask I will start a stop watch , recording the amount of time it takes for the sulphur precipite to make the solution opaque therefore being unable to see the cross look from directly above . When this happens I will stop the clock and record the result . For each concentration repeat three times .
