Chapter 12 Practice Concentrations

1) What is the mass percentage of H ₂ O ₂ in a solution that is 1.75 m H ₂ O ₂ (the solvent is water)?

• 1.75 m H₂O₂ is ________% H₂O₂ by mass.

2) A 12.5 M H₂SO₄ solution has a density of 1.66 g/mL. What is the molality of the solution? The solvent is water.

• 12.5 M H₂SO₄ is _________ m H₂SO₄.

3) How much potassium cyanide (KCN) would you need to weigh our to make 500.0 mL of a 0.275 M potassium cyanide solution?

• Weigh out _________ g of KCN.

4) How do you prepare 555 grams of an aqueous solution of KI that is 7.6% potassium iodide (KI) by mass?

• Dissolve ______ g KI in _______ g water.

5) If a 150.0 g sample of rubbing alcohol (a solution of isopropanol, C₃H₇OH, in water) contains 97.0 g isopropanol, calculate the mole fraction of each component of the sample, the mass percentage of isopropanol in the sample, and the molality of isopropanol in the sample.

• The mole fraction of isopropanol in the sample is ________________.

• The mole fraction of water in the sample is ________________.

• The mass percentage of isopropanol in the sample is __________________.

• The molality of the isopropanol in the sample is ___________________.

All original site content ©2008 Charles Taylor. Page updated: February 04, 2008.