Materials
Boileezers (boiling chips)
Desiccant
0.17M acetic acid (acidified water)
Solution of Sodium thiosulfate
Granular zinc
Iodine crystals
Zinc ion and iodine-iodide-triiodide ion in water
Solid zinc iodide
Mineral oil
Silver nitrate
Magnesium turnings
3M Hydrochloric acid (HCl) solution
2 boiling tubes
1 large tube (we used a small)
Pipet
Beakers (to hold tubes)
Bunsen burner
PART 1
Procedure
Get a boiling tube and label it R (reactants). Weigh out 2g of granular zinc and 2 g of iodine crystals and add to boiling tube “R”.
Get a large test tube and label it C (colored solution) and another boiling tube and label it P (products). Place one boiling chip into tube “P”.
Put 5 mL of acetic acid into tube “R” and swirl. After 1 minute the solution should be a red-brown color. With a pipet remove 30 drops of the solution and put into tube “C”. Continue swirling tube “R” until the reaction is complete (solution has turned clear).
Decant all the solution from “R” into “P”, leaving the gray solid behind. Any solution left behind in “R” can be “washed” and put into “P”. To wash the substance, add 1mL of acidified water to “R”. Swirl and pour the solution into “P”. Repeat 2 more times.
Heat the “R” boiling tube over a Bunsen burner until all the moisture is gone. Cork and put in a Ziploc bag with desiccant.
Heat the “P” boiling tube until all the water has evaporated and only a white substance remains. Cork and put in a Ziploc bag with desiccant.
To identify the isolated substances we have to first compare it to the standards
Iodine crystals: Small. Sphere-like. Gray-blue in color. Metallic.
Granular zinc: Small. Mixture of long and round pieces. Metallic. Silver.
Zinc ion and iodine-iodide-triiodide ion in water: Dark red-brown. Viscous liquid.
Solid zinc