Anonymous
Anonymous asked in Science & MathematicsChemistry · 1 month ago

Chemistry?

The recommended procedure for preparing a very dilute solution is not to weigh out a very small mass or measure a very small volume of stock solution. Instead, it is done by a series of dilutions.

A sample of 0.9597 g of KMnO4 was dissolved in water and made up to the volume in a 500.0−mL volumetric flask. A 2.000−mL sample of this solution was transferred to a 1000−mL volumetric flask and diluted to the mark with water. Next, 10.00 mL of the diluted solution was transferred to a 250.0−mL flask and diluted to the mark with water.

(a) Calculate the concentration (in molarity) of the final solution.

 

(b) Calculate the mass of KMnO4, needed to directly prepare the final solution.

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  • 1 month ago
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    (a)

    (0.9597 g KMnO4) / (158.0339 g KMnO4/mol) / (500.0 mL) ×

    (2.000 mL) / (1000 mL) × (10.00 mL) / (250.0 mL) = 9.7164 × 10^-10 mol/mL =

    9.716 × 10^-13 mol/L

    (b)

    (0.9597 g KMnO4) / (500.0 mL) × (2.000 mL) / (1000 mL) × (10.00 mL) =

    3.839 × 10^-5 g

    or

    (9.7164 × 10^-10 mol/mL) × (250.0 mL) × (158.0339 g KMnO4/mol) =

    3.839 × 10^-5 g

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