Instructions for Half of a Chemistry Lab

Instructions for half of a chemistry lab

Use pipettes to measure the buffer, Na2S2O3 and the H2O2 solutions. Use a burette to

measure the KI solution and a graduated cylinder for the distilled water. Use the graduated

dropper provided to measure the starch.

Prepare solution A (except for the H2O2) as accurately as possible in a clean 400 mL beaker.

Use a 100 mL graduated cylinder to measure the H2O. Place the beaker on a piece of white

paper so that the colour change may be observed as soon as it begins. Record the temperature of

the solution. One student should record to the nearest second the time that the second student

adds, with thorough stirring, the accurately measured 10.0 mL of peroxide solution. Once the

solution is mixed well, further stirring is unnecessary.

As soon as the solution has been well mixed, half fill a boiling tube with the

solution and suspend it in the regulated water bath provided. The temperature of this solution

should also be recorded. Watch both solutions attentively for the appearance of a colouration

uniformly throughout.