Hydration Lab

The purpose of this experiment is to become familiar with some properties of water and solutions and distinguish between such terms as diffusion, dialysis and osmosis. In this experiment, we will be going over water residue, water of hydration, solutions and dialysis. For Water Residue section, place about 1 mL of tap water on a clean watch glass and gently heat it until water has evaporated. Record if there is any residue and repeat this procedure using deionized water. Next, for Water of Hydration section, obtain a few crystals of hydrated copper(II) sulfate, describe their appearance on the data sheet. Then place the crystals into an evaporating dish, place a watch glass over the top of the dish and heat to drive off the water. Move the
Observe and record the results. For Diffusing part, place a small beaker of water in a place where it will not be disturbed. Then drop one small crystal of potassium permanganate into the beaker and record the appearance. For Recrystallization part, place approximately 5-7 grams of sodium thiosulfate in a test tube and heat the mixture the solid appears to melt. Then allow the solution to cool to room temperature. If no crystals appear when the test tube is cooled, the solution is supersaturated. Next drop one crystal of sodium thiosulfate into the supersaturated solution and describe what happens on the data sheet. The Dialysis section is divided into two parts: test for copper(II) ion and test for starch. For Test for Copper(II) ion part, take 1 mL of the water from the dialysis beaker and place it in a test tube, and then add a few drops of concentrated ammonium hydroxide and record the observations. Lastly, for Test for Starch section, take 1 mL of the water from the dialysis beaker and place it in a test tube. Add a few drops of iodine solution and record