Question

Pre-lab Questions for Experiment-7 Hydrates and the Determination of the Formula of a Hydrate 1) What is the color for anhydrous salt of copper (ID) sulfate (CuSO.)? What is the color for ionic hydrate compound of copper (II) sulfate pentahydrate (CuSO4 5H20)? 2) How would you test a colorless rystalline compound to determine if it was a hydrate? 3 1.2008 g of a hydrate of CuSO4" XH O after heated has a mass of 0.7676 g. Calculate the mass percent of water and determine the chemical formula of this hydrate.

Answer 1

Color of anhydrous copper(II) sulphate is white

Anhydrous copper(II) sulphate is white solution Ionic hydrated cuSo_4S H_2O is Blue CuSo_4 S H_2O rightarrow CuSo_4 + S H_2O (2) Hydrates if coloured However if the compound is an colourless hydrate still. It is possible to determine that it is a hydrate Hydrates are compound in which H_2O molecules are linked in crystalline form Therefore on heating the water of crystallization is last and loss in weight occurs, which confirms that the heated compound is a hydrate. Solution Mass of CuSO_4 times H_2O = 1.2008g Mass after heating = 0.7676g Mass of H_2O present = (1.2008 - 0.7676) in hydrated cuSO_4 times H_2O = 0.4332G %MASS OF H_2O = 36.07% Now 18 X/18X + 159.5 times 100 = 36.07 X = 4.99 approx 5 therefore formula = CuSO_4 . S H_2O anhydrous copper(II) sulphate is white color of hydrated copper(II) sulphate is blue By heating the weight loss suggests that the compound was a hydrate mass percent of water = 36.07

color of hydrated copper(II) sulphate is blue

By heating the weight loss suggests that the compound was a hydrate

mass percent of water=36.07

Formula of the compound is CuSO4.5H2O

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