Types of Chemical Reactions & Solution Chemistry Chapter 4

Sections 4.1-4.2 Homework You will need to read these sections and take notes. If you have questions while reading, write them in your notes and then ask tomorrow.

4.3: The Composition of Solutions Chemical reactions often take place when two solutions are mixed. To perform stoichiometric calculations we must know TWO things: 1. The nature of the reaction (what happens) 2. Amounts of chemicals present (usually expressed in molarity)

Molarity Molarity (M)= moles solute per liter of solution Exercise 4.1 Calculate the molarity of a solution prepared by dissolving 11.5g of solid NaOH in enough water to make 1.50L of solution.

Answer 0.192M

Exercise 4.2 Calculate the molarity of a solution prepared by dissolving 1.56g of HCl in enough water to make 26.8mL of solution.

Answer 1.60M

Exercise 4.3: Concentration of Ions Give the concentration of each type of ion in the following solutions A. 0.50M Co(NO3)2 B. 1M Fe(ClO4)3

Answers A. 0.5oM Co+2, 1.0M NO3- B. 1M Fe+3, 3M ClO4-

Exercise 4.4 Concentration of Ions Calculate the number of moles of chloride ions in 1.75L of 0.001M zinc chloride.

Answer 0.004mol Cl-

Exercise 4.5: Concentration & Volume Typical blood serum is about 0.14M NaCl. What volume of blood contains 1.0mg NaCl?

Answer 0.12mL blood

Exercise 4.6: Solutions of Known Concentration To analyze the alcohol content of a certain wine, a chemist needs 1.00L of an aqueous 0.200M K2Cr2O7 solution. How much potassium dichromate must be weighed out to make this solution?

How do you make a solution? Read and Study p. 143 We will make a solution tomorrow!

What is Dilution? How do you dilute a solution? How do you calculate the concentration of a diluted solution? How can you determine the volume of stock solution you need to make a desired dilute solution?

Exercise 4.7: Concentration & Volume What volume of 16M sulfuric acid must be used to prepare 1.5L of a 0.10M sulfuric acid solution?

Answer 9.4mL

4.4 Types of Chemical Reactions Precipitation reactions Acid-Base reactions Oxidation-reduction reactions (Redox)

Precipitation Reactions When two solutions are mixed, an insoluble solid sometimes forms (precipitate) Example: Barium nitrate reacts with potassium chromate What are the products? Which product is the precipitate?

p.150 or in summer assignment info!! Solubility Rules LEARN THEM!! p.150 or in summer assignment info!!

Exercise 4.8 Using the solubility rules predict what will happen when the following pairs of solutions are mixed: A. Potassium nitrate & Barium Chloride B. Sodium sulfate & Lead (II) nitrate C. Potassium hydroxide & iron (III) nitrate

Answers A. No reaction B. Lead (II) sulfate C. Iron (III) hydroxide

4.6 Describing Reactions in Solutions Molecular equation: shows reactants and products Complete Ionic equation: represents the actual forms of the reactants and products in solution Net Ionic equation: includes only those solution components directly involved in the reaction.

Exercise 4.9: Writing Equations for Reactions Write the molecular equation, the complete ionic equation, and the net ionic equation A. Aqueous potassium chloride is added to aqueous silver nitrate to form a silver chloride precipitate plus aqueous potassium nitrate.

Exercise 4.9 Con’t B. Aqueous potassium hydroxide is mixed with aqueous iron(III) nitrate to form a precipitate of iron(III) hydroxide and aqueous potassium nitrate.

4.7 Stoichiometry of Precipitation Reactions Calculate the mass of solid NaCl that must be added to 1.50L of a 0.100M AgNO3 solution to precipitate all the Ag+ ions in the form of AgCl.

Answer 8.77g NaCl

Another one… When aqueous solutions of Na2SO4 and Pb(NO3)2 are mixed, PbSO4 precipitates. Calculate the mass of PbSO4 formed when 1.25L of 0.0500M Pb(NO3)2 and 2.00L of 0.0250M Na2SO4 are mixed.

Answer 15.2g PbSO4

Stoichiometry of Acid-Base Reactions What volume of 0.50M sulfuric acid is required to neutralize 50.0mL of 1.45M aluminum hydroxide? Answer: 220mL

Stoichiometry of Acid-Base reactions What mass of chloric acid would be needed to completely neutralize 50.0g of magnesium hydroxide? Answer: 51.1g