CHM 2045C Name: _________________
Module Eight Homework Packet-Jespersen

Module Eight: Solutions/Oxidation & Reduction (McMurry Chapter 4) ppt

A. _____(02) Solution Properties-From Lecture(4.1, 4.2) Answers

B. _____(02) Factors Affecting Rate of Dissolving-From Lecture(11.4) Answers

C. _____(02) Writing Ionzation Reactions acids/salts Sect 4.3, 4.4 Answers

D. _____(03) Solution Preparation Problems-Section 4.7 Answers

E. _____(03) Solution Dilution Problems-Section 4.7 Answers

F. _____(05) Solution Reaction Problems-Section 4.8, 4.9, 5.6 Answers

G. _____(05) Rewrite Equations Ionically Section 4.3 Answers

H. _____(06) Redox Equations-Sections-Section 5.1, 5.2 Answers

I. _____ (02 Solution Discussion Question-Chapter 4, 5 Answers

K.  ____ (02) Solution Definitions-Chapters 4, 5, From Lecture Answers

L. _____(03) pH calculations-Section 16.1 Answers

______(35) Total = ______%

 

M-8 Required Homework:

______(35) M-8 Pretest Hardcopy Homework Packet

______(10/20) M-8 Multiple Choice (MC) Homework/Exam (Blackboard Online)

G1. ______(20) Hard Copy (Acid/base Media) Writing Net Ionic Reactions Homework (Sect 4.3)

H1.______(20) REDOX Post Lab

 

Part A: Solution Properties

Back in Module 1 a solution was introduced as a homogeneous mixture of a solute and solvent and you included them in your matter chart for Part A of Module 1.  A solution is defined as a homogeneous mixture of two or more substances.  The two new words are introduced, solute and solvent. Although we usually think of solutions to be liquids, Table 13.1 (14.1 Corwin 6th )lists some common examples of solutions whose physical state correspond to that of a solvent.

14_01_Table.jpg

 

Module 8 we start with six properties of a true solution which are not listed in chapter 4 as a separate list.  You will write five of these six properties for Part A:

1.  It is homogeneous mixture of two or more components, solute and solvent

 2.  It has variable composition, that is, the ratio of solute and solvent may be varied.

 3. The dissolved solute is molecular or ionic in size

 4. It may be colored or colorless but it is usually transparent

 5. The solute remains uniformly distributed throughout the solution and will not settle out with time (every drop has exactly the same concentration)

 6. The solute generally can be separated from the solvent by purely physical means (for example evaporation or distillation)

 

Part A: Solution Properties 02 points

List five of the six properties of a true solution:

 

(1)

 

 

(2)

 

 

(3)

 

 

 

(4)

 

 

 

(5)

 

 

 

(6)

 

 

 

 

 

 

 

 

Module 8: Solutions Chapter 4/5

Part B: Factors Affecting Rate of Dissolving  

Part B covers the dissolving process. A discussion of solubility and temperature plus solubility and pressure of a gas in a solution is as follows.

14_02_Table.jpg

The following answers the first question:

State two factors greatly affecting the solubility of a gas in a liquid:

(1) Temperature (increased temperature of a solvent also generally increases the kinetic energy of the solute  and the gas solute acquire more of a tendency to escape from the solvent. Therefore, Cooling the solvent increased the solubility of a gas in a liquid solvent.)

 (2) Pressure (increasing the pressure (partial pressure) of a gas solute increases the solubility proportionally of that solute in the liquid (Henrys Law)

The properties of liquids dissolved in liquids focus on the main property which is polarity. Now is the time to review polar covalent bonds chapter 7. Polar covalent bonds depend on the electronegativities of the two elements.

electronegativityChart

If two elements differ in electronegativity between 0.4 and 1.7, then polar covalent bonds are formed. If the difference between the two atoms is greater than 1.7 then ionization takes place. A solution containing ions must be dissolved by polar molecules as a solvent.

dipoles

Next you must understand the three dimensional geometry of the molecules to determine if a molecule is polar. Molecules with polar covalent bonds have dipoles, which are vectors, created by the polar covalent bonds When they are summed, if there is a net moment of force the molecule is polar. However, it is possible for a compound to have polar covalent bonds and be nonpolar when the net summation of the vectors total zero .

The Like Dissolves Like Rule depends on the polarity of the molecules of the solute and the solvent (Table14.3 Corwin 6th is the same as Table 13.3 on page 378..

fg14_T03

 

What is the main factor affecting the solubility of a liquid in a liquid:

 (3) Nature of the solute and solvent: the like dissolves like rule. The general principle that solubility is greatest when the polarity of the solute is similar to that of the solvent

LikeDissolvesLike

LikeDissolvesLikeSolid

The discussion of the dissolving leads to the rate of dissolving, which is the next question in Section B of Module 8(They do not list #3 below.).

RateOfDissolving

 State four factors which governs the rate of dissolving a solid in a liquid:

 1.  Particle Size (increased surface area increases rate of solution i.e powders have greater surface area than crystals
                                and will dissolve faster)

 2. Temperature (increased temperature of solvent generally increases rate of solution,  except gases in liquids is opposite)

 3. Concentration of Solution- when the solute and solvent are first mixed the rate of dissolving is at a maximum, as saturation approaches the rate of dissolving slows

 4. Agitation or stirring-the effect of agitation is kinetic which increases the rate of solution.

 

SolubilitySolidsVsTemperature

Part B: Factors Affecting Rate of Dissolving 02 points

 

State two factors greatly affecting the solubility of a gas in a liquid and explain:

 

(1)

 

 

(2)

 

 

 

What is the main factor affecting the solubility of a liquid in a liquid and explain the rule:

 

 

(3)

 

 

 

 

State four factors which governs the Rate of dissolving a solid in a liquid:

 

(1)

 

 

(2)

 

 

 

(3)

 

 

 

(4)

 

 

Part C: Writing Ionization Reactions 

There is a discussion of the solubility of compounds in water which produce ionic solutions. Strong Acids and Weak Acids are shown in table 14.2 below:
15_02_Table.jpg

The convention for writing the iodination reaction is wrong as the weak acid should be a double arrow (reversible reaction), but the reversible reaction is not discussed until 2046, therefore he shows a single arrow (which will be counted wrong on the test).


Likewise, Strong and Weak Bases are show:

15_03_Table.jpg

And the ionization reaction of a weak base should also be a reversible arrow or double arrow

Soluble Salts are show as a single direction arrow, while Insoluble salts have a double arrow for a reversible reaction. Strong (Soluble) Electrolytes a and Weak Electrolytes (Insoluble in water) are later in the text

These sections lead to section 14.11 Writing Net Ionic Reactions from Corwin.

 

 

 

 

 

From the textbook (Corwin 6th ):

15_05_Table.jpg

StrongWeakElectrolyles

StrongWeakAcids

Part C: Writing Ionization Reactions 02 points

(Strong Acids/Weak Acids/Strong Bases/Weak Bases/

Soluble Salts and Oxides of Nonmetals and Metals)

 

Write the ionization reactions for the following:

(1) Strong Acid: HCl (aq)

 

 

 

 

(2) Weak Acid: HC2H3O2 (aq)

 

 

 

 

(3) Strong Base: NaOH (aq)

 

 

 

 

(4) Weak Base: NH3 (aq)

 

 

 

 

(5) Soluble Salts: NaCl (aq)

 

 

 

 

(6) Oxides of Nonmetals: CO2 (g)

 

 

 

 

(7) Oxides of Metals: CaO (s)

 

 

Part D: Solution Preparation Problems   

There are three measurements of solutions in preparation problems of which two will be given and the third will be asked in Part D for preparing a solution in a laboratory. The three are: mass of solute, volume of solution (not volume of solvent-you should know the difference), and the concentration of the solution.

There are six methods of measuring the concentration of a solution: Molarity, Weight (Mass) Percent, Volume Percent, Molality, Parts Per Million, and Normality.  Problems for Part D will focus mainly on Molarity, but Weight percent is also fair game. The other four methods of measuring concentration will not be asked in Part D.

 
Mass%Grams75

M8EPercentConcentration

 If the problem states the mass of the solute and the volume of the solution prepared is given, then the Molarity is unknown for one problem type. The other common problem is how to make a known volume of a known concentration of a solution and you have to find the mass.

SolutionPrepGtoML75

M8EMolarConentration

SolutionPrepMLtoG75

Part D: Solution Preparation Problems 03 points

 

1. How many grams of solute are needed to prepare 250 ml of a 0.0100 M KMnO4?

 

 

 

 

 

 

 

 

 

2. 20 grams of AgNO3 were placed in a 250 ml volumetric flask, calculate the Molarity of the Solution.

 

 

 

 

Part E: Solution Dilution/Concentration Problems 

In Section 13.10 of Chapter 13 there is a second type of method for preparing a solution.  On page 391 Dilution of a Solution is discussed. On page 392 is Example 13.10 of diluting a more concentrated solution.  At the end of the chapter are two additional exercises #65 and #68 on page 401-402.

M8EDilutionSolution

Part E: Solution Dilution/Concentration Problems 03 points

 

1. How many milliliters of a 12 M HCl (concentrated) are required to make 2.00 L of a 1.00 M HCl?

 

 

 

 

 

2. A stock bottle of concentrated nitric acid indicates that the solution is 67.0 HNO3 by mass and has a density of 1.40 g/ml. Calculate the molarity of concentrated nitric acid.

 

 

 

Part F: Solution Reaction Problems

 

 

 

 

 

M8FSolutionReaction

 

 

AcidBaseTitration

AcidBaseTitrationH2SO4

 

AcidBaseTitrationBase

 

 

 

 

 

 

 

 

 

Part F: Solution Reaction Problems 5 points

Acid-Base Neutralization (2.5 Points):

1. Calculate the molarity of a Calcium hydroxide solution if 18.50 mL of it requires 28.27 mL of a 0.0125 M HCl to reach its neutralization point.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

REDOX Titration: (2.5 Points)(Ask for Balanced)

2. A KMnO4 (aq) solution is to be standardized by titration against As2O3(s), A 0.1156 g sample of As2O3 requires 27.08 mL of KMnO4. What is the molarity of the KMnO4?

 

As2O3 + MnO4 1- + H2O + H1+ -------> H3AsO4 + Mn 2+

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Module Eight: Part G Rewriting Equations Ionically

 

In Section 14.11 on page 427 is the discussion of Net Ionic Equations.  To do Part H, REOX Equations, you need to be good at writing equations in aqueous solutions ionically. Example Exercise 15.15 (14.15 Corwin 7th ) on page 428 and Exercise 15.16 (14.16 Corwin 7th )on page 429 demonstrate the process step by step. You should work the Practice Exercise on page 429 plus the end of the chapter exercises #71-76 on page 436.

StrongWeakElectrolyles

 

StrongWeakAcids

 

The following Rules are written at the top of the Part G test:

Show as ions: soluble salts (aq) and strong acids (aq); leave as molecules/formula units insoluble salts (s), weak acids (aq), covalent molecules. (Strong hydroxide bases are hydroxides which are also soluble salts are written ionically.)

 

 

Strong Acids are: Perchloric Acid; Hydrochloric Acid; Nitric Acid; Sulfuric Acid; Hydrobromic Acid; Hydroiodic Acid.

 

Strong Bases are: Sodium hydroxide, Potassium hydroxide, Calcium hydroxide, Barium hydroxide, Strontium hydroxide

 

Here are a set of worked examples:

 

1. KOH (aq) + HNO3(aq) KNO3(aq) + HOH(l)

 

Decide which compounds should be split into ions:

K|OH (aq) + H|NO3(aq) K|NO3(aq) + HOH(l)

Strong base strong acid soluble salt covalent molecule

 

Rewrite the ionic species as ions, and leave the rest as compound formulas:

K1+(aq)+OH1-(aq)+H1+(aq)+NO31-(aq)K1+(aq)+NO31-(aq)+HOH(l)

 

Cancel the Spectator Ions:

K1+(aq)+OH1-(aq)+H1+(aq)+NO31-(aq)K1+(aq)+NO31-(aq)+HOH(l)

 

 

Final Net Ionic Answer:
1. KOH (aq) + HNO3(aq) KNO3(aq) + HOH(l)

OH 1-(aq) + H 1+(aq) HOH (l)

------------------------------------------------------------------------------

2. CuSO4 (aq) + Na2CO3 (aq) CuCO3 (s) + Na2SO4 (aq)

Decide which compounds should be split into ions:

 

Cu|SO4 (aq) + Na2|CO3 (aq) CuCO3 (s) + Na2|SO4 (aq)

Soluble Salt Soluble Salt Insoluble salt Soluble Salt

 

 

 

Rewrite the ionic species as ions, and leave the rest as compound formulas

Cu2+(aq)+SO42-(aq)+2Na1+(aq)+CO32-(aq)

CuCO3(s) + 2Na1+(aq)+SO42-(aq)

 

 

Cancel the Spectator Ions:

Cu2+(aq)+SO42-(aq)+2Na1+(aq)+CO32-(aq)

CuCO3(s) + 2Na1+(aq)+SO42-(aq)

Final Net Ionic Answer:
2. CuSO4 (aq) + Na2CO3 (aq) CuCO3 (s) + Na2SO4 (aq)

 

Cu 2+ + CO3 2- CuCO3 (s)

 

--------------------------------------------------------------------------------------------

 

3. NaOH (aq) + NH4NO3 (aq) NaNO3 (aq) + NH3 (g) + HOH (l)

 

Decide which compounds should be split into ions:

 

Na|OH (aq) + NH4|NO3 (aq) Na|NO3 (aq) + NH3 (g) + HOH (l)

Strong Base Soluble Salt Soluble Salt molecular molecular

 

Rewrite the ionic species as ions, and leave the rest as compound formulas:

Na1+(aq)+OH1-(aq)+NH41+(aq)+NO31-(aq)

Na1+(aq)+NO31-(aq) + NH3 (g)+HOH(l)

 

Cancel the Spectator Ions:

Na1+(aq)+OH1-(aq)+NH41+(aq)+NO31-(aq)

Na1+(aq)+NO31-(aq) + NH3 (g)+HOH(l)

 

Final Net Ionic Answer:
3. NaOH (aq) + NH4NO3 (aq) NaNO3 (aq) + NH3 (g) + HOH (l)

OH 1- + NH4 1+ NH3 (g) + H2O (l)

 

------------------------------------------------------------------------------------------

 

 

 

4. BaBr2 (aq) + ZnSO4 (aq) BaSO4 (s) + ZnBr2 (aq)

 

Decide which compounds should be split into ions:

 

Ba|Br2 (aq) + Zn|SO4 (aq) BaSO4 (s) + Zn|Br2 (aq)

Soluble Salt Soluble Salt Insoluble salt Soluble Salt

 

Rewrite the ionic species as ions, and leave the rest as compound formulas

Ba2+(aq)+ 2Br1-(aq) + Zn2+(aq) + SO42-(aq)

BaSO4(s) + Zn2+aq) + 2Br1-(aq)

Cancel the Spectator Ions:

Ba2+(aq) + 2Br1-(aq) + Zn2+(aq) + SO42-(aq)

BaSO4(s) + Zn2+(aq) + 2Br1-(aq)

 

Final Net Ionic Answer:
4. BaBr2 (aq) + ZnSO4 (aq) BaSO4 (s) + ZnBr2 (aq)

 

Ba 2+ + SO4 2- BaSO4 (s)

 

---------------------------------------------------------------------

 

5. Cr(OH)2 (s) + HCl (aq) First Complete the Product:

 

Cr(OH)2 (s) + 2HCl (aq) CrCl2 (aq) + HOH (l)

 

Decide which compounds should be split into ions:

Cr(OH)2 (s) + 2 H|Cl (aq) Cr|Cl2 (aq) + HOH (l)

Insoluble Salt Strong Acid Soluble Salt Molecular

 

Rewrite the ionic species as ions, and leave the rest as compound formulas:

Cr(OH)2 (s) +2H1+(aq) + 2Cl1-(aq)Cr2+(aq)+ 2Cl1-(aq) + HOH(l)

 

 

 

 

 

 

 

 

Cancel the Spectator Ions:

 

Cr(OH)2 (s)+ 2H1+(aq)+ 2Cl1-(aq) Cr2+(aq)+ 2Cl1-(aq) + HOH(l)

 

 

Final Net Ionic Answer:
5. Cr(OH)2 (s) + 2 HCl (aq) CrCl2 (aq) + H2O (l)

Cr(OH)2 (s) + 2 H 1+ (aq) Cr 2+ (aq) + 2 H2O (l)

 

From the Corwin Textbook:

NetIonicReactions

NetIonicReaction2

 

NetIonicReactionPrecipitation

NetIonicReactionPrecipitation2

 

 

Video:

http://www.brightstorm.com/science/chemistry/chemical-reactions/net-ionic-equation/

 

 

Module Eight: Part G Rewriting Equations Ionically 5 points

Rewrite the following (unbalanced) equations ionically, cancel spectator ions and then balance the net ionic reactions. Show as ions: soluble salts and strong acids and strong bases; leave as molecules/formula units insoluble salts, weak acids, covalent molecules.

 

Strong acids are: Perchloric Acid; Hydrochloric Acid; Nitric Acid; Sulfuric Acid; Hydrobromic Acid; Hydroiodic Acid.

 

Strong bases are Sodium hydroxide, Potassium hydroxide, Calcium hydroxide, Barium hydroxide and Strontium hydroxide

 

1. KOH (aq) + HNO3(aq) KNO3(aq) + HOH(l)

 

 

 

 

 

 

2. CuSO4 (aq) + Na2CO3 (aq) CuCO3 (s) + Na2SO4 (aq)

 

 

 

 

 

 

3. NaOH (aq) + NH4NO3 (aq) NaNO3 (aq) + NH3 (g) + HOH (l)

 

 

 

 

 

 

4. BaBr2 (aq) + ZnSO4 (aq) BaSO4 (s) + ZnBr2 (aq)

 

 

 

 

 

 

5. Cr(OH)2 (s) + HCl (aq)

 

 

 

 

Module Eight Homework Packet

 

Module 8 Part H: Redox Equations 6 points

 

A separate Study Guide will be distributed along with additional Homework.

Balance the following redox equations written in net ionic form:

Acid Media: (3 points)

 

1. C2O4 2- (aq) + MnO4 1- (aq) + H 1+ (aq) Mn 2+ (aq) + CO2 (g) + HOH (l)

 

 

 

 

 

half equation:

 

 

 

 

 

 

half equation:

 

 

 

 

 

 

Basic Media (3 points)

 

2. Bi2O3 (s) + OH 1- (aq) + OCl 1- (aq) → BiO3 1- (aq) + Cl 1- (aq) + HOH (l)

 

 

 

 

half equation:

 

 

 

 

 

half equation:

 

 

 

 

 

 

 

Module Eight Homework Packet

 

Part I: Solution Discussion Questions 2 points

Answer the following:

 (1) Define oxidation and reduction in terms of electron transfer.

 

   

(2) In an oxidation reduction equation, what is the oxidizing agent?

 

  

What is the reducing agent?

 

 

(3) How can you recognize whether a reaction is a redox reaction or not?

  

 

 

(4) Name three types of reactions which are NOT oxidation reduction and give at least one example

 

 

 

(5) What is the equivalence point in a titration of an acid and a base? Is there a difference between the equivalence point and the end point of the titration when using an acid/base indicator to determine the end point?

 

 

 

 

 

Key Strokes:

Negative Sign then Log Key then [H3O1+] then Exe = pH

 

Key Strokes:

2nd Sign then Log Key then Neg Sign then pH then Exe = [H3O1+]

Part L: pH Scale Calculations (Section 15.8-15.9) 3 points

What is the pH and pOH of the following solutions:

 

pOH = 14.00 pH Kw = 1.00 x 10-14 = [H3O1+][OH1-]

 

(1) 0.0100 M HCl

 

 

 

 

 

 

(2) 0.0055 M Mg(OH)2

 

 

 

 

 

(3) The pH of vinegar is 2.85, calculate the [H3O1+]:

 

 

 

 

 

 

(4) Easy Off Oven Cleaner has a pH of 11.70. What is the [H3O1+] and [OH1-]?

 

 

 

 

 

Module Eight Homework Packet

Part K: Solution Definitions 2 points

Fill in the blank with word for the definition listed:

 

1.______________When dynamic equilibrium is established between undissolved solute in a

Solution, we say the solution is __.

 

2. ______________Any solution containing less solute than it could hold at equilibrium is said

To be a(n) _______________solution.

 

3. ______________That part of a solution which you are dissolving.

 

 

4. ______________That part of a solution which does the dissolving (or the media of the

solution).

 

5. ______________are dispersions in which that the dispersed matter has one or more

dimensions in the range of 1 to 1000 nm and has the unique ability to scatter light.

 

6. ______________of a solution is the number of moles of solute per Liter of solution.

 

 

7. ______________of a solution is the grams of solute per 100 grams of solution

 

 

8._______________of a solution is the milliliters of solute per 100 milliliters of solution.

 

9.______________homogeneous mixture of a solute and a solvent.

 

10._____________ .Any solution containing more solute than it could hold at equilibrium is said

To be a(n) _______________solution.

 

Define Normality; define equivalent.

 

 

 

 

 

What is the difference between a solution, colloidal solution, colloidal suspension, and a suspension