Method: Place the scales provided on a flat surface and check the calibration with the 10gm weight included. (Use the tweezers to move items on and off the scales)
Weigh out approximately 500mg (1/2 gram) of powder for testing. Record the accurate weight and dissolve the sample in approximately 50ml of distilled water.
When the sample is fully dissolved, use a syringe from the kit to drip in 5ml of white vinegar. Note the cloud of white precipitate that forms with each drop. Let the precipitate settle.
Weigh and record the weight of the dry laboratory filter paper provided in the Kit. You will then need a small plastic funnel. Fold the paper so that it fits inside the small plastic funnel. Pour the mixture (liquid and precipitate) into the funnel so that it drains through the filter paper. To ensure that all the precipitate has been washed into the filter paper, rinse the container containing the mixture using a syringe of distilled water.
Repeat the process by adding another 5 ml of vinegar to the clear filtrate. Again let the precipitate that forms settle, then pour through the same filter paper and rinse the precipitate again. Repeat until the further addition of vinegar leads to no visible precipitate.
Place the filter paper in an oven set at low heat (~1000 C), and
allow the filter paper to dry. Re-weigh the filter paper plus the dried precipitate.
Calculate the weight of the total precipitate by subtracting the weight of the filter paper.
The % purity of the original sample is obtained by: (Weight of salt/ Weight of precipitate) x 90