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Determining mass of solute in a volume of solution

Example 3:

How many grams of solute are in 2.4 mL of a .02 M H2O2 solution?

Answer:

Step 1

Write out the definition for molarity. M = moles solute/ liters of solution

Step 2

Identify the quantities given in the question volume of solution moles of solute molarity molar mass 2.4 mL ? unknown .02 M H2O2 1 mol = 34 g H2O2

Step 3

Use the definition of molarity to cancel out volume and determine the grams of solute. grams solute = [liters of solution] [molarity] [ molar mass of solute] g solute = 1.6 x 10-3 g H2O2

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Dr. Walt Volland, all rights reserved revised April 2, 2005