My prediction is the higher the concentration of HCL the quicker the Sodiumthiosulphate will react with it.I think this because there are more particles colliding with each other

• Conical flask
• Hydrochloric acid
• Sodiumthiosulphate
• Stop clock
• Paper with X in the middle
• Pipette
• Beaker
• Measuring cylinder

Fair test: To make the experiment fair we repeated it two times on the same day so that the room temperature was the same throughout the test. We cleaned the equipment after the experiment so they were clean and did not have any of the mixed solution left in it.

Method:

Our method was-

• Collect apparatus
• Set up apparatus
• Pour 25 ml into beaker of HCL
• Pour 25 ml Sodiumthiosulphate
• Set timer
• Start the timer when solutions are together
• Record time
• Repeat using 1mol
• Repeat using 0.5mol
• Repeat using 0.25mol
• Repeat using    0.125mol
• Repeat and record time

Results:

Test 1

Test 2

Average table

Conclusion:

When I reacted hydrochloric acid with sodiumthiosulphate, I predicted that the higher the concentration of Hcl the quicker the sodiumthiosulphate would react and my prediction was right. This is what happened when I added the Hcl to sodiumthiosulphate the solution went cloudy and then the x disappeared and I know this because I could not see the x any more. To prove that my prediction was right I done this I added hcl which was 2 MOL to sodiumthiosulphate and then I waited for the x to disappear and it disappeared in 42.87 (s)  the first time, 49.41 (s) the second time and when I added Hcl which was 0.125 MOL to sodiumthiosulphate and then I waited for the x to disappear and the x disappeared in 85.59 (s) the first time and 89.37 (s) the second time, so that means that my prediction was right because I said the higher the concentration of Hcl the faster the reaction time will be.

Evaluation:

I think I have done the experiment well enough that I could write up a good conclusion because I knew what I had to write up because my prediction matched my results. I done the test as well as I could and I tried to make it fair as I could by making sure I used separate measuring tubes for each chemical and I done other things to make it fair. If I could do the test again I would try and do it as fairly and I would take my time so I would get more accurate results and I would repeat it three times.