What is the percentage by mass of KClO, in a saturated solution at 40 C?

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ncchemist | eNotes Employee

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You have left a numerical subscript off of your chemical compound.  KClO does not exist.  You must mean KClO4 which is potassium perchlorate.  In order to calculate the percentage by mass of a saturated solution, we must first look up the aqueous solubility of KClO4.  This cannot be calculated, the value must simply be looked up.  The aqueous solubility of KClO4 is 1.5 g per 100 mL water.  Since the density of water is 1 g per mL, we know that 100 mL of water is the same as 100 g of water.  So we know that 1.5 g of KClO4 in 100 g of water is a saturated solution.  Since both values are in terms of mass (grams), we can divide the two and multiply by 100 to get a percentage.  The percentage by mass of a saturated solution of KClO4 is 1.5/100 = 0.015 * 100 = 1.5%.