12.3

Concentration of Solutions

12.3Concentration is a measure of the amount of solute

dissolved in a solution.There are many ways to measure the concentration.

12.3Concentration is a measure of the amount of solute

dissolved in a solution.There are many ways to measure the concentration. Percent (part per hundred), ppb, ppm, etc

Usually by volume if using a liquid dissolved in a liquid

Usually by mass if using a solid dissolved in a liquid

Molality (m) Mole fraction Molarity (M)

12.3Concentration is a measure of the amount of solute

dissolved in a solution.There are many ways to measure the concentration. Percent (part per hundred), ppb, ppm, etc

Usually by volume if using a liquid dissolved in a liquid

Usually by mass if using a solid dissolved in a liquid

Molality (m) Mole fraction Molarity (M)

These are all quantitative. What would be a qualitative word for measuring concentration?

12.3Percent =

12.3Percent = mass of solute x 100

mass of solution

12.3Example 1: What is the % concentration of a

solution made by dissolving 17g of sucrose in 183g of water?

12.3Example 2: What would the solution in #1 be in

ppm? ppb?

12.3Example 3: What would the % concentration be of

a solution made by combining 45g of KCl in 100g of water?

12.3Example 4: What would be the new concentration if

155g of water were added to the solution in #3?

12.3Molality =

12.3Molality = moles of solute / kilograms of solvent

What is an advantage to using molality over molarity?

12.3Molality = moles of solute / kilograms of solvent

What is an advantage to using molality over molarity?

Molality is unaffected by temperature.

12.3Example 5: What is the molality of a solution made

by adding 16.1g of chlorine gas to 5000g of water?

12.3Example 6: What is the molality of a solution made

by adding 125g of iodine to 750g of carbon tetrachloride (CCl4)?

12.3Mole fraction =

12.3Mole fraction = moles of solute / total moles

12.3Example 7: What is the mole fraction of sulfur

dioxide in a solution containing 128g of sulfur dioxide dissolved in 1500g of carbon dioxide?

12.3Example 8: A gas mixture contains 50.4g of

dinitrogen monoxide and 65.2g of oxygen gas. What is the mole fraction of dinitrogen monoxide?

12.3Molarity =

12.3Molarity = moles of solute / liters of solution

12.3Example 9: What is the molarity of a solution

formed by mixing 10.0g of sulfuric acid (H2SO4) with enough water to make 100.0mL of solution?

12.3Example 10: Vinegar is a solution of acetic acid

(CH3COOH). What is the molarity of a solution produced when 125g of acetic acid is dissolved in water to make 1.50L of solution?

12.3Example 11: How many grams of bromine are

needed to prepare 0.500L of a 0.0100M solution of bromine in water?

12.3Example 12: What volume (in mL) of a 0.500M

solution of copper (II) sulfate is needed to react with an excess of aluminum to provide 11.0g of copper?

12.3Example 13: Commercial hydrochloric acid, HCl, is

12.0M. Calculate the mass of HCl in 250mL of solution.

12.3Example 14: An excess of zinc is added to 125mL

of 0.100M HCl. What mass of zinc chloride is formed?

12.3Example 15: Yellow CdS pigment is prepared by

reacting ammonium sulfide with cadmium nitrate. What mass of CdS can be prepared by mixing 2.50L of 1.25M cadmium nitrate solution with an excess of ammonium sulfide solution?

12.3When solvent is added to a solution, the number of

moles does not change, but the molarity does.

12.3When solvent is added to a solution, the number of

moles does not change, but the molarity does.

When diluting a solution, only the volume changes, not the moles of solute.

12.3When solvent is added to a solution, the number of

moles does not change, but the molarity does.

M1 V1 = M2 V2

M = molarity V = volume

12.3Example 16: How many milliliters of 3.0M H2SO4 are

required to make 450mL of 0.10M H2SO4?

12.3Example 17: How many milliliters of 5.0M K2Cr2O7

solution must be diluted in order to prepare 250mL of 0.10M solution?

Chapter 12 Test15 multiple choice (4 points each)8 problems (5 points each)1 extra credit (5 points)

heterogeneous mixture (colloids and suspensions) vs homogeneous mixture (solutions)miscible vs immisciblesaturated, unsaturated, and supersaturatedsolubility graphs (5 questions)“like dissolves like”solubility of gases vs solubility of solidsprocess of solvation in aqueous solvent = enthalpy of solution

dissolution of solute (breaking bonds, endothermic)solvent pulling solute apart

hydration (reforming bonds, exothermic)water forming bonds with solute

ways to increase the rate of solvationmolarity (M)molality (m)% compositionmole fractiondilutions involving molaritystoichiometry involving solutions