A concentrated aqueous ammonia solution has a density of 0.90 g/mL and is 28.0% by mass ammonia (17.04 g/mol).Determine the molar concentration of this solution.

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Quizplus · Accepted Answer

To find the molar concentration, first calculate the mass of ammonia in 1 L of solution: 0.90 g/mL * 1000 mL = 900 g of solution. 28% of this is ammonia, so 0.28 * 900 g = 252 g of ammonia. The molar mass of ammonia is 17.04 g/mol, so the number of moles is 252 g / 17.04 g/mol = 14.78 mol. Therefore, the molarity is approximately 15 M.

A Concentrated Aqueous Ammonia Solution Has a Density of 0