Chapter 12 Lecture

Basic ChemistryFourth Edition

Chapter 12 Solutions12.1 Dilution and Chemical Reactions in Solution

Learning Goal Calculate the new concentration or volume of a diluted solution. Given the volume and concentration of a solution, calculate the amount of another reactant or product in a reaction.

© 2014 Pearson Education, Inc.

In a dilution• a solvent, usually water, is added to a solution

that increases the volume• the concentration of the new solution will be

less due to the larger volume

© 2014 Pearson Education, Inc.

Dilutions

© 2014 Pearson Education, Inc.

In a dilution the amount of solute does not change, only the volume of the solution.

C1V1 = C2V2 Where C is the concentration of the solution (it can be molarity or percent concentration), and V is the volume of the solution.

Dilutions, Changing Volume

Grams or molesof solute in

concentrated solution=

Grams or moles of solute in diluted

solution

© 2014 Pearson Education, Inc.

Dilutions, Changing Volume

When water is added to a concentrated solution, there is no change in the number of particles. The solute particles spread out as the volume of the diluted solution increases.

© 2014 Pearson Education, Inc.

Guide to Calculating Dilution Quantities

© 2014 Pearson Education, Inc.

What is the final molarity of the solution when 0.180 L of 0.600 M KOH is diluted to 0.540 L?

Learning Check

© 2014 Pearson Education, Inc.

What is the final molarity of the solution when 0.180 L of 0.600 M KOH is diluted to 0.540 L?

Step 1 Prepare a table of the concentrations and volumes.

Solution

© 2014 Pearson Education, Inc.

What is the final molarity of the solution when 0.180 L of 0.600 M KOH is diluted to 0.540 L?

Step 2 Rearrange the dilution expression to solve for the unknown quantity.

Solution

© 2014 Pearson Education, Inc.

What is the final molarity of the solution when 0.180 L of 0.600 M KOH is diluted to 0.540 L?

Step 3 Substitute the known quantities into the dilution expression and calculate.

Solution

© 2014 Pearson Education, Inc.

What is the volume, in milliliters, of a 5.4% (m/v) NH3 solution that can be prepared by diluting 50.0 mL of a 15% (m/v) NH3 solution?

Learning Check

© 2014 Pearson Education, Inc.

What is the volume, in milliliters, of a 5.4% (m/v) NH3 solution that can be prepared by diluting 50.0 mL of a 15% (m/v) NH3 solution?

Step 1 Prepare a table of concentrations and volumes of the solutions.

Solution

© 2014 Pearson Education, Inc.

What is the volume, in milliliters, of a 5.4% (m/v) NH3 solution that can be prepared by diluting 50.0 mL of a 15% (m/v) NH3 solution?

Step 2 Rearrange the dilution expression to solve for the unknown quantity.

Solution

© 2014 Pearson Education, Inc.

What is the volume, in milliliters, of a 5.4% (m/v) NH3 solution that can be prepared by diluting 50.0 mL of a 15% (m/v) NH3 solution?

Step 3 Substitute the known quantities into the dilution expression and calculate.

Solution

© 2014 Pearson Education, Inc.

In a chemical reaction,

• the volume and molarity of a solution are used to determine the moles of a reactant or product

Chemical Reactions in Solution

© 2014 Pearson Education, Inc.

Guide to Calculations, Solutions in Chemical Reactions

© 2014 Pearson Education, Inc.

Given the following reaction, determine how many liters of 1.50 M HCl solution completely react with 5.32 g of zinc? Zn(s) + 2HCl(aq)

H2(g) + ZnCl2(aq)

Learning Check

Zinc reacts when placed in a HCl solution.

© 2014 Pearson Education, Inc.

Given the following reaction, determine how many liters of 1.50 M HCl solution completely react with 5.32 g of zinc?Zn(s) + 2HCl(aq) H2(g) + ZnCl2(aq)Step 1 State the given and needed

quantities.

Solution

© 2014 Pearson Education, Inc.

Given the following reaction, determine how many liters of 1.50 M HCl solution completely react with 5.32 g of zinc?Zn(s) + 2HCl(aq) H2(g) + ZnCl2(aq)Step 2 Write a plan to calculate the needed quantity or concentration.

Solution

Gramsof Zn

Molar massMolar mass

Molesof Zn

Mole-mole factor

Mole-mole factor

Moles of HCl MolarityMolarity

Liters of HCl

© 2014 Pearson Education, Inc.

Given the following reaction, determine how many liters of 1.50 M HCl solution completely react with 5.32 g of zinc?Zn(s) + 2HCl(aq) H2(g) + ZnCl2(aq)Step 3 Write equalities and conversion factors, including mole-mole and concentration factors.

Solution

© 2014 Pearson Education, Inc.

Given the following reaction, determine how many liters of 1.50 M HCl solution completely react with 5.32 g of zinc?Zn(s) + 2HCl(aq) H2(g) + ZnCl2(aq)Step 3 Write equalities and conversion factors, including mole-mole and concentration factors.

Solution

© 2014 Pearson Education, Inc.

Given the following reaction, determine how many liters of 1.50 M HCl solution completely react with 5.32 g of zinc?Zn(s) + 2HCl(aq) H2(g) + ZnCl2(aq)Step 4 Set up problem to calculate the needed quantity or concentration.

Solution

© 2014 Pearson Education, Inc.

Concept Map, Substance A to Substance B