Sodium Tiosulphate Investigation

Planning

I will investigate the effect of temperature on the rate of reaction of sodium thiosulphate and acid. I will keep the acid and sodium thiosulphate concentration constant and vary the temperature. The maximum volume in total will be 60cm³ cubed.

The rate of reaction will be found by finding the time for a cross drawn on a piece of paper with a pencil and placed under a conical flask to disappear from sight when looked at from above. It disappears because the sulphur formed is a solid and forms a cloud of fine particles through which you cannot see.

Simple Plan:
• Add 30ml of water to a measuring cylinder
• Add 20ml of Sodium Thiosulphate to the same cylinder
• Heat (or cool) the solution to one of the desired temperatures (shown below)
• Add 10ml of acid to a separate cylinder
• Add the acid to a conical flask placed above a piece of paper with a cross on it
• Mix the Sodium Thiosulphate with the acid and begin timing the exp...