Chapters 4, and 5. Solution: Electrolyte: Nonelectrolyte:

Unit 2Chapters 4, and 5

Solution:

Electrolyte:

Nonelectrolyte:

Aqueous Reactions

Dissolving compounds and molecules

The diagram below represents an aqueous solution of one of the following compounds: MgCl2, KCl, or K2SO4. Which solution does the drawing best represent?

Solubility of Ionic Compounds

Double Replacement Reaction:

Ionic Equation:

Net Ionic Equation:

Precipitation Reactions

Predict the identity of the precipitate that forms when solutions of BaCl2 and K2SO4 are mixed. Write the balanced chemical equation for the reaction.

Acid:

Base:

Strong acid or base vs weak acid or base:

Acid-Base Reactions

Neutralization Reactions

Write a balanced molecular equation for the reaction between aqueous solutions of acetic acid and barium hydroxide. Write the net ionic equation for this reaction.

Oxidation-Reduction:

Oxidation:

Reduction:

Oxidation-Reduction Reactions

Oxidation Numbers

Determine the oxidation number of sulfur in each of the following:

a.) SCl2

b.) Na2SO3

c.) SO42-

By acid:

By soluble salt:

Oxidation of Metals

Write the balanced molecular and net ionic equation of aluminum with hydrobromic acid.

Activity Series

Molarity:

Solution Concentration

Calculate the molarity of a solution made by dissolving 23.4 g of sodium sulfate in enough water to form 125 mL of solution.

Concentration of Electrolytes

What are the molar concentrations of each of the ions present in a 0.025 M aqueous solution of calcium nitrate?

Converting molarity, moles, and volume

How many grams of Na2SO4 are required to make 0.350 L of 0.500 M Na2SO4?

Dilution

How many milliliters of 3.0 M H2SO4 are needed to make 450 mL of 0.10 M H2SO4?

Titration:

Titrations

How many grams of Ca(OH)2 are needed to neutralize 25.0 mL of 0.100 M HNO3?

Chapter 5Thermochemistry

Thermodynamics:

Thermochemistry:

Thermochemistry

Types of Energy

Units of Energy

System:

Surroundings:

System and Surroundings

Transferring Energy

Internal Energy

Endothermic:

Exothermic:

Endothermic vs. Exothermic

Enthalpy

Heat transfer from system to surroundings

Heat transfer from surroundings to system

Enthalpy

CH4(g) + 2 O2(g) CO2(g) + 2 H2O(l)

ΔH = -890 kJ

Enthalpies of Reaction

How much heat is released when 4.50 g of methane gas is burned in a constant pressure system?

Hess’s Law

The enthalpy of reaction for the combustion of C(s) to CO2(g) is -393.5 kJ/mol, and the enthalpy for the combustion of CO to CO2 is -283.0 kJ/mol:

C(s) + O2(g) CO2(g) ΔH = -393.5 kJ

CO(g) + ½ O2(g) CO2(g) ΔH = -283.0 kJ

Use this information to calculate the enthalpy for the combustion of C(s) to CO(g)

Standard Enthalpy of Formation

Formation Reactions

Enthalpies of Formation

Hess’s Law

Equation:

Using Enthalpies of Formation

Which of the following is the correct net ionic equation for the reaction of sodium hydroxide and nitric acid?

(A) H+ + OH- H2O

(B) Na+ + NO3- NaNO3

(C) NaOH + HNO3 NaNO3 + H2O

(D) Na+ + OH- + H+ + NO3- NaNO3 + H2O

(E) Na+ + OH- + 2 H+ NaOH + H2

Example Questions

What volume of distilled water should be added to 20 mL of 5 M HCl to prepare a 0.8 M solution?

(A) 100 mL

(B) 105 mL

(C) 125 mL

(D) 200 mL

Compound Δhof (kJ/mol)

CO2(g) -393.5

CaO(s) -635.5

CaCO3(s) -1,207.1

The decomposition of CaCO3(s) is shown in the equation to the right. Using the data in the table, which of the following values is closest to the ΔHrxn of the decomposition of CaCO3(s)?

(A) -2,240 kJ/mol

(B) -180 kJ/mol

(C) 180 kJ/mol

(D) 1,207 kJ/mol

(E) 2,240 kJ/mol

A 0.2 mol sample of MgCl2(s) and a 0.1 mol sample of KCl(s) are dissolved in 500 mL of water. What is the concentration of Cl- in the resulting solution?

(A) 0.15 M

(B) 0.30 M

(C) 0.60 M

(D) 1.0 M

2 CH6N2 + 5 O2 2 N2 + 2 CO2 + 6 H2O(g)

The combustion of methylhydrazine, is represented above. The ΔH of this reaction is -1,303 kJ/mol. What would bout the ΔH per mole CH6N2 if the reaction produced H2O(l) instead of H2O(g)? (The ΔH for the condensation of H2O(g) to H2O(l) is -44 jk/mol)

(A) -1,171 kJ

(B) -1,259 kJ

(C) -1,347 kJ

(D) -1,435 kJ

What is the final concentration of Pb2+ ions when a 100 mL 0.2M Pb(NO3)2 solution is mixed with a 100 mL 0.30 M NaCl solution?

(A) 0.005 M

(B) 0.010 M

(C) 0.015 M

(D) 0.025 M