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Question

The method of preparation for an aqueous solution calls for 5.0 grams of anhyrdrous sodium sulfate, Na2SO4. The sodium sulfate available is crystalline hydrated sodium sulfate, NaSO4 * 10 H2O. How many grams of this hydrated compound should be used in place of the anhydrous compound when preparing the reagent? FW of Na2SO4 is 119.05 g/FW, MW of water is 18.02 g/mol. Hint: the number of moles of crystalline hydrated sodium sulfate must equal the number of moles of anhydrous sodium sulfate

Answer 1

No great problem. Divide 5 g by 119.05 to get the moles required. Then find the mol wt of the hydrated salt and multiply by the moles from before.