Chapter 4 Acid/base, precipitaton, redox Reactions in Solution Chapter 4 Acid/base, precipitaton, redox

Water Is an angular or bent molecule therefore polar Types of solvation Hydration Dissociation Dissociation equations NaCl(s) → Na+ (aq) + Cl-(aq) BaCl2(s)→ Ba2+ (aq) + 2Cl-(aq)

Electrolytes – Strong electrolytes Weak Electrolytes Salts Increase [ ] = Strong Acids HX + H2O→ H3O+ (aq) + X- (aq) Strong bases MOH (s) → M+ (aq) + OH- (aq) Weak Electrolytes weak acids weak bases

Non-electrolytes- Molecular substances that are not acids

Solution Concentrations

Most Common unit of concentration is Molarity (M) Example What is the molarity of a solution made by dissolving 38.6g calcium chloride in enough water to make 475.0mL of solution?

Ex. 2 What volume ofj 3.67M aluminum chloride contains 2.5g of solute? Ex. 3 How many moles of ammonium ions are contained in 35.6mL of 0.639M ammonium sulfide?

Preparing Solutions to a specific concentration For solids- Use desired molarity to convert desired volume of solution into mass of solute For stock solutions- MSVS = MNVN solve for the volume of stock solution needed and dilute with water to the total desired volume

Ex. How would you prepare 500.mL of 0.3750N sodium chloride from: Solid sodium chloride? A 5.00M stock solution?

Precipitation Reactions

Precipitate: Solubility Rules:

Molecular Equation: Total Ionic Equation: Net Ionic Equation:

Predict the products for the following reactions Predict the products for the following reactions. Write the net ionic equation. Magnesium chloride + lead (II) nitrate Barium chlorate + sodium sulfate Sodium hydroxide _ copper(II) chloride

You do these Iron (II) sufate + potassium chloride Al(NO3)3 + Ba(OH)2 Calcium chloride + sodium sulfate Lead (II) nitrate + sodium chloride K2S + Ni(NO3)2

Precipitation stoichiometry Identify the species present in combined solution Write a balanced NIE Calculate moles of reactants Determine the LR Calculate moles of product(s) as required Convert moles to other units as necessary

Stoichiometry of Precipitation Reactions What mass of precipitate forms when 100.0 mL of 3.75 M AgNO3 reacts with 100.0 mL of 4.50 M NaCl?

What volume of 3.38 M CuSO4 is needed to completely precipitate all of the hydroxide ions in 45.6 mL of 4.39 M NaOH?

100.0 mL of 0.32 M Pb(NO3)2 and 100.0 mL of 0.41 M Na2CrO4 Consider a mixture of: 100.0 mL of 0.32 M Pb(NO3)2 and 100.0 mL of 0.41 M Na2CrO4 a) What mass of precipitate can be formed? b) What is the molar concentration of all ions remaining in solution?

A mixture is prepared by adding 25. 0 mL of 0 A mixture is prepared by adding 25.0 mL of 0.386 M aluminum chloride to 75.0 mL of 0.300 M potassium hydroxide. What is the concentration of all ions remaining in solution?

Determine the molarity of all ions in solution for the example below: 100.0 mL 100.0 mL 0.450 M 0.380 M NaOH (aq) + CuSO4 (aq) 

Determine the molarity of all ions in solution for the example below: 75.0 mL 35.0 mL 0.210M 0.8325M CaCl2 (aq) + AgNO3 (aq) 

Acid Base Reactions

Acid base rxns are Proton transfer rxns Arrhenius Acids: produce _______________in aqueous sln Bases: produce ____________in aqueous sln Bronsted-Lowry Acids: proton ____________ Bases: proton ____________ Acid base rxns are Proton transfer rxns Redox rxns are electron transfer rxns

Lewis Acids and bases “Have pair will share” Bases are electron pair donors Acids are electron pair acceptors Usually ammonia with a trigonal compound of Boron Group 5A with BX3

Conjugate Acid-Base Pairs Conjugate acids : species formed after base accepts H+ Ex: Base: NH3, F-, H2O CA: Conjugate base: species left once acid donate H+ Ex: Acid: HCl , HC2H3O2 , H2S , HS- CB:

Amphoteric – substances that can act as an acid or a base Acid: have hydrogen to donate Bases: are – charged so it can accept a H+ Ex: HS- HSO4- H2O H2PO4-

Stoichiometry of Acid-Base Reactions Definitions: volumetric analysis Titration Titrant Analyte equivalence point Indicator end point "Standardizing the solution"  

Examples: What volume of 0.500 M Ba(OH)2 will react completely with 25.0 mL of 0.200 M HCl?

A 50.0 mL sample of an ammonia solution is analyzed by titration with HCl. The titration required 39.47 mL of 0.0984 M HCl to reach the endpoint. What was the concentration of the ammonia solution?

Suppose that 5. 00 g of solid iron (III) oxide is added to 20 Suppose that 5.00 g of solid iron (III) oxide is added to 20.0 mL of 0.500 M HCl. a) What is the concentration of Fe3+ when all of the HCl has reacted? b) What mass of Fe2O3 will not be reacted?  

A mixture is prepared by adding 50. 0 mL of 0. 200 M HCl to 45 A mixture is prepared by adding 50.0 mL of 0.200 M HCl to 45.0 mL of 0.180 M KOH. Is the resulting solution acidic, basic, or neutral?