Question number 1. You dissolve 346. mg of a compound (A w B x C y D z ) in wate

Question

Question number 1.

You dissolve 346. mg of a compound (AwBxCyDz) in water producing 17.81 mL of solution and use the photometer and standard solutions to find that the concentration of the A is 1.18 x 10-2 M. The molar mass of A is 166.28 g/mol.

Moles of A in the solution sample:________________________________

Mass of A in the solution sample: _________________________________

Mass % of A in the compound: _______________________________

Moles of A in 100 grams of the compound: ________________________________

Explanation / Answer

moles of A =17.81x1.18 x 10-2 / 1000 = 2.1016 x 10^ -4

mass of A in sample = moles of A x molar mass =2.1016 x 10^ -4 x 166.28 = 0.034945 g = 34.945 mg

Mass % of A =34.945 mg /346. mg x 100 = 10.099 = 10.1 %

Moles of A in 100g of compound = (2.1016 x 10^ -4 / 0.346 ) x 100 = 0.06074 g

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