INVESTIGATION Nº1

OBJECTIVE: DETECT THE PRESENCE OF VITAMIN C IN DIFFERENT SUBSTANCES.

MATERIALS: 3 beakers; 3 Petri's dishes; dropper; spoon.

Concentrated starch suspension in water; lemon juice; vitamin C complex; synthetic juice; iodine solution.

PROCEDURE: *Put, in each Petri's dish, equal amounts of starch suspension; then add equal amounts of iodine solution in each one.

*In one of the dishes, add vitamin C complex (which have been dissolved in water previously), recording the amount of drops, which are needed for the iodine solution, in the starch suspension, to tern white.

*Repeat the same procedure with the lemon juice and with the synthetic juice (which have been dissolved in water previously).

NOTE: the vitamin C complex and the synthetic juice should be dissolved in water and the lemon should be squeeze just before the investigation is carried out, for vitamin C may denature when oxygen is present...