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Mr. Storie
40S Chemistry
Final Exam Review
40S CHEMISTRY FINAL EXAM PROBLEM REVIEW SHEET:
**THIS IS NOT A COMPLETE REVIEW. CONTINUE TO READ ALL COURSE NOTES, GO OVER
ALL WORKSHEETS, HANDOUTS, AND THE MID-TERM EXAM TO BE BETTER PREPARED.
To prepare for this exam:
1. Make a schedule and stick to it.
2. Be sure you have a complete set of notes, and STUDY them.
3. Re-do old tests, quizzes and assignments.
4. Do it again, and again, and again.
5. Seek help if you are confused or need clarification. (I’ll be in room 118)
Unit # 1 - Atomic Structure
 Isotopes & Relative atomic mass
 Electromagnetic Radiation (wavelength, frequency, and energy)
 Energy level diagrams & Orbital diagrams
 Electronic configuration
 Periodic table trends
 Bonding
 Lewis Structures
 VSEPR Theory
Unit # 2 – Kinetics (Reaction Rates)
 Calculating Rates
 Factors affecting rate
 Ways to speed up a reaction
 Collision Theory
 Energy diagrams (reaction pathway)
 Rate Laws
Unit # 3 – Equilibrium
 Equilibrium Constants (expressions)
 Equilibrium constant calculations
 Significance of equilibrium constant value
 Le Chatelier’s Principle
 Heterogeneous and homogeneous equilibria
 Reaction Quotients
Unit # 4 – Acids & Bases
 Properties
 Strong vs. Weak
 pH & pOH
 Salts of Weak acids and bases
 Titrations
 Ionization constants and percent ionization (dissociation)
 Common ion effect
Mr. Storie
40S Chemistry
Unit # 5 – Reduction and Oxidation and Electrochemistry
 Oxidation Numbers
 Balancing using oxidation numbers
 Balancing using ion-electron method (in acid or base)
 Galvanic Cells
 Standard reduction potentials
 Electrolysis (reactions occurring at anode and cathode)
 Faraday’s laws
Final Exam Review
ATOMIC STRUCTURE
1. Give the electron configuration for a neutral atom of manganese, strontium, and iron.
2. Write the short hand notation for the electron configuration of phosphorus, tungsten, and gold.
3. What is the wavelength of light with a frequency of 5.6 x1020 Hz?
4. What is the frequency of light with energy 4.3x 10-15 J ?
5. What is the energy of blue light that has a wavelength of 650 nm?
6. Draw an orbital box diagram of chromium. Which electrons would it lose to form a 2+ ion?
7. Calculate the number of orbitals in the third energy level. Show your work.
8. Draw Lewis dot diagrams and use VSEPR to predict the shapes of the following molecules. Include
valence electron count and account for all electrons.
a) AlCl3
b) PO4-3
c) PH3
d) SF6
e) OCl2
9. Identify which molecules in question 9 are polar.
10. What is the general trend observed for ionization energy? Explain this trend for ionization energies;
include reasoning for the trend in a group and the trend in a period.
11. What are the trends observed for electronegativity, electron affinity, and metallic character?
12. By considering the electron arrangement for the atoms oxygen and nitrogen, explain why the first
ionization energy of oxygen is lower than that of nitrogen in spite of the fact that the trend predicts the
opposite. (Hint: draw the orbital box diagram of each)
Mr. Storie
40S Chemistry
Final Exam Review
13. Draw Lewis dot diagrams for the following molecules. Show the valence electron count and account for
all electrons.
a. H2S
b. XeF4
14. Using Lewis dot diagrams and VSEPR theory predict the shapes of the following molecules. Show the
valence electron count and account for all electrons. Indicate the number of bonding pairs and lone
pairs of electrons. Draw the 3-D representation of the molecules.
a. NF3
b. PI5
15. Explain the difference between polar covalent bonds, non-polar covalent bonds, ionic bonds and
coordinate covalent bonds.
KINETICS PROBLEMS
1. The reaction, A + 2B  Products, was found to have the rate law, Rate = k[A][B]2. While holding the
concentration of A constant, the concentration of B was increased from x to 3x. Predict by what factor
the rate of the reaction will increase.
2. For the hypothetical reaction A + B  Products, the following initial rates of reaction have been
measured for the given reactant concentrations.
Experiment
1
2
3
a.
b.
c.
d.
e.
[A] (M)
0.010
0.015
0.010
[B] (M)
0.020
0.020
0.010
Rate (mol/(L∙hr))
0.020
0.030
0.005
Calculate the order for reactant A.
Calculate the order for reactant B.
Calculate the overall order for the reaction.
Write the rate law expression.
Solve for the specific rate constant, k. 5000
3. For a reaction with the rate law - rate = k [A]n [B]m - Determine the factor by which the rate changes if
both [A] and [B] are doubled given the following values of “n” and “m”. Show all your work.
a. n=0, m=2
b. n=2, m=2
c. n=1, m=3
Mr. Storie
40S Chemistry
Final Exam Review
+
4. For the chemical reaction H2O2 + 2H + 2I  I2 + 2H2O
the rate law expression is Rate = k[H2O2][I-]. The following mechanism has been suggested.
H2O2 + I-  HOI + OHOH- + H+  H2O
HOI + H+ + I-  I2 + H2O
a. Define the term “intermediate” and identify all intermediates included in this reaction.
b. Determine which of the steps is the RDS, and explain how the conclusion was reached.
5. Draw a Potential Energy Diagram for the following exothermic reaction:
2 SO2 (g) + O2 (g)  2 SO3 (g) ΔH° = -198 kJ
Label your diagram with the following information:
a. reactants (write the actual reactants)
b. products (write the actual products)
c. activated complex
d. activation energy
e. ΔH° = -198 kJ
6. If ammonia gas, NH3, reacts at a rate of 0.090 mol/Ls according to the reaction
4 NH3 (g) + 5 O2 (g)  4 NO (g) + 6 H2O (g)
a. at what rate does oxygen gas react under the same conditions? 0.11 mol/Ls
b. what is the rate of formation of water? 0.14 mol/Ls
c. What is the rate of production of nitrogen monoxide? 0.090 mol/Ls
7. The reaction
A + B + C  E + F + G
Trial
[A]
(mol/L)
1
1.0
2
2.0
3
1.0
4
1.0
5
1.5
was studied at 0°C and the following data was collected:
[B]
[C]
Initial Rate
(mol/L)
(mol/L)
(mol/L•s)
2.0
2.0
1.66
2.0
2.0
3.33
4.0
2.0
1.66
2.0
4.0
6.65
5.0
?
7.25
a. What is the rate law for this reaction?
b. What is the value of the rate constant 0.42
c. What is the rate if [A] = 1.5 mol/L, [B] = 2.5 mol/L, [C] = 0.25 mol/L? 0.039 mol/Ls
d. What is the [C] in trial 5? 3.4 mol/L
Mr. Storie
40S Chemistry
8. Write the rate laws for the following elementary reactions
Final Exam Review
a. N2 (g) + 3 H2 (g)  2 NH3 (g)
b. N2 (g) + 2 O2 (g)  2 NO2 (g)
c. H2 (g) + Cl2 (g)  2 HCl (g)
Determine the value of k in 8(a), when [N2] = 0.50 mol/L and
[H2] = 1.5 mol/L and NH3 is produced at a rate of 2.5 mol/Ls. 1.5
EQUILIBRIUM PROBLEMS
1. At 773 K, the reaction
2 NO (g) + O2 (g)  2 NO2 (g)
produces the following concentrations:
[NO] = 3.49 X 10-4M; [O2] = 0.80M; [NO2] = 0.25M.
a. What is the equilibrium constant expression for this reaction?
b. What is the equilibrium constant for the reaction? 6.4 x 105
2. Phosphorous pentachloride decomposes to phosphorous trichloride according to this equation:
PCl5 (g)  PCl3 (g) + Cl2 (g)
Keq = 1.00 x 10-3
At equilibrium, [PCl5] = 1.00M and [Cl2] = 3.16 x 10-2M.
a. Calculate the concentration of PCl3. 3.16 x 10-2 M
b. Chlorine gas, Cl2 (g) is toxic. If we could manipulate the pressure of the container for this
reaction, how can we minimize the formation of this gas? Explain using your knowledge of Le
Chatelier’s principles.
3. Consider the reaction:
2 HBr (g)  H2 (g) + Br2 (g)
Initially, 0.25 mol of hydrogen and 0.25 mol of bromine are placed in 500 mL reaction vessel and
heated. The Kc for the reaction is 0.020. Calculate the concentrations at equilibrium. 0.78 M, 0.11
M, 0.11 M
4. For the given reaction of methanol, the equilibrium concentrations were found to be [CO] = 0.170 M, [H2]
= 0.322, [CH3OH] = 0.0406. Find the value of Kc. 0.434
CH3OH (g)  CO (g) + 2 H2 (g)
Mr. Storie
40S Chemistry
5. Hydrogen peroxide can be decomposed as follows:
H2O2 (l)  H2 (g) + O2 (g)
Final Exam Review
(endothermic)
Equilibrium is established in a 10 L flask at room temperature. Predict the direction of the
equilibrium shift.
a. hydrogen gas is added to the flask.
b. The temperature is raised to 500 ºC.
c. The entire mixture is compressed into a smaller volume.
ACIDS AND BASES PROBLEMS
1. You have water at 25o to which you add 0.050 M NaOH.
Complete the chart:
[H3O+]
Before adding NaOH
After adding NaOH
[OH-]
2. This time with a weak base. Let’s add 0.0050 M NH4OH. Kb =1.77x 10-5.
[H3O+]
[OH-]
Before adding NH4OH
After adding NH4OH
3. If an acid has a hydronium concentration of 0.000036 M, what is the pOH of the solution? 9.6
4. What is the hydroxide ion concentration of a solution with a pH of 4.9? 8.0 x 10-10 M
5. What is the % ionization of a 2.5 M solution of acetic acid (Ka = 1.76 x 10-5). 0.27 %
6. The pH of 0.50M HNO2 is 4.85. Find Ka. 3.9 x 10-10
7. What is the concentration of phosphoric acid if 15.0 ml of the solution is neutralized by 38.5 mL of a 0.15
M NaOH solution? 0.13 M
8. Suppose 3.5% of a weak solution of 0.020 M monoprotic acid is ionized. Calculate the Ka.
2.5 x 10-5
Mr. Storie
40S Chemistry
9. Complete and balanced the following reactions:
Final Exam Review
a. Sulphuric acid plus potassium hydroxide 
b. Phosphoric acid + Ca(OH)2 
c. Nitric acid and magnesium hydroxide 
10. A solution was made by dissolving 28.5 g of KOH in 0.50 L of water. If 0.250 L of this solution was
titrated with 0.136 L of H2SO4, what is the molarity of the acid? 0.938 M
ELECTROCHEMISTRY
1. Consider the particles:
Na+, Mg, Cl-, F2, H2O
a) Which can be oxidized? ___________________________________
b) Which can be reduced? ____________________________________
c) Which is the best reducing agent? ____________________________
2. For each of the following cells (which may or may not be written according to the standard line notation)
indicate which half-cell is the anode and which is the cathode.
a) Zn│Zn2+║Cu2+│Cu
Anode: ________
Cathode: _______
b) Ag│Ag+║Ni2+│Ni
Anode: ________
Cathode: _______
c) Sn│Sn2+║Au3+│Au
Anode: ________
Cathode: _______
3. Sketch a galvanic cell between copper and barium. Show the direction of electron flow and ion migration,
identify the anode and cathode, the species present in each half-cell, indicate the voltage on a voltmeter,
and label the electrodes. Also show the half-reactions, overall cell reaction and the Emf calculation.
4. For each of the following cells write half-reactions, give the balanced net cell reaction, and calculate the
Emf of the cell.
a) Al3+(aq) + Mg(s) → Al(s) + Mg2+(aq)
b) Cr(s)│Cr3+(aq) (1.0 mol/L)║Ag+(aq) (1.0 mol/L)│Ag(s)
5. Write out anode and cathode reactions for the electrolysis of the following.
a) CaCl2(l)
b) CuI2(l)
6. Using standard reduction potentials, predict the anode and cathode half-reactions in the electrolysis of the
following solutions.
a) CaBr2(aq)
b) FeSO4(aq)
7. How many coulombs of charge must pass through a cell in order to deposit 9.45 g of zinc from a solution
of zinc nitrate?
8. What happens in an oxidation reaction in terms of electrons?
Mr. Storie
40S Chemistry
9. What happens in a reduction reaction in terms of electrons?
Final Exam Review
10. Assign oxidation numbers to each atom in the following compounds.
a) H3SO4
b. HNO3
11. Which reactant in the following reaction is oxidized and which is the oxidizing agent?
CO(g) + PbO(s) → CO2(g) + Pb(s)
12. Balance the following equation using the oxidation number method.
HBr + HBrO3 → Br2 + H2O
13. Balance the following equations in acid or base as indicated in brackets.
a. Cu + HNO3 → Cu2+ + NO2 + H2O
(acid)
b. N2O4 + Br- → NO2- + BrO3(base)
14. Examine the cell below and answer the questions that follow.
Sn
Ag
Ag +
NO3-
a)
b)
c)
d)
e)
f)
g)
h)
Sn2+
NO3-
Cathode reaction: ___________________________________________
Anode reaction: ____________________________________________
Overall reaction: ___________________________________________
What is the cell voltage? _____________
Label anode and cathode.
Indicate the direction of travel of ions and electrons.
While the cell operates which electrode gains in mass? __________
While the cell operates which electrode decreases in mass? ___________
Mr. Storie
EXAM REVIEW KEY:
40S Chemistry
Final Exam Review
ATOMIC STRUCTURE
1. Give the electron configuration for a neutral atom of manganese, strontium, and iron.
Mn: 1s2 2s2 2p6 3s2 3p6 4s2 3d5
Sr: 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2
Fe: 1s2 2s2 2p6 3s2 3p6 4s2 3d6
2. Write the short hand notation for the electron configuration of phosphorus, tungsten, and gold.
P: [Ne] 3s2 3p3
W: [Xe] 6s1 4f14 5d5 (*ep)
Au: [Xe] 6s1 4f14 5d10 (*ep)
3. What is the wavelength of light with a frequency of 5.6 x1020 Hz?
λ=c/f
= (3 x 108) / (5.6 x 1020 )
= 5.35 x 10-13 m/s
4. What is the frequency of light with energy 4.3x 10-15 J ?
f = E/h
= (4.3 x 10-15) / (6.626 x 10-34)
= 6.48 x 1018 Hz
5. What is the energy of blue light that has a wavelength of 650 nm?
f=c/λ
= (650 x 10-9) / (3 x 108)
= 4.62 x 1014 Hz
E = hf
= (6.626 x 10-34)(4.62 x 1014)
= 3.1 x 10-19 Js/pho
6. Draw an orbital box diagram of chromium. Which electrons would it lose to form a 2+ ion?
2 - 4s electrons
7. Calculate the number of orbitals in the third energy level. Show your work.
# of orbitals = n2
32 = 9 orbitals
8. Draw Lewis dot diagrams and use VSEPR to predict the shapes of the following molecules. Include
valence electron count and account for all electrons.
a) AlCl3
b) PO4-3
c) PH3
d) SF6
e) OCl2
a) *ionic bond – 3 bonding / 0 lone = trigonal planar
b) 4 bonding/ 0 lone = tetrahedral
c) 3 bonding/ 1 lone = trigonal pyramidal
d) 6 bonding/ 0 lone = octahedral (*eO)
e) 2 bonding / 2 lone = bent
Mr. Storie
40S Chemistry
9. Identify which molecules in question 8 are polar.
C, E
Final Exam Review
10. What is the general trend observed for ionization energy? Explain this trend for ionization energies;
include reasoning for the trend in a group and the trend in a period.
Increases across, decreases down.
Across – more proton attraction, down – more shielding and further away from nucleus
11. What are the trends observed for electronegativty, electron affinity, and metallic character?
EN - Increases across, decreases down.
EA – Increases across, decreases down.
MC – Decreases across, increases down.
12. By considering the electron arrangement for the atoms oxygen and nitrogen, explain why the first
ionization energy of oxygen is lower than that of nitrogen in spite of the fact that the trend predicts the
opposite. (Hint: draw the orbital box diagram of each)
½ filled and completely filled sublevels are more stable – N (2p3), O (2p4)
13. Draw Lewis dot diagrams for the following molecules. Show the valence electron count and account for
all electrons.
a. H2S
b. XeF4
2+6=8–4=4
8 + 4(7) = 36 – 8 = 28
14. Using Lewis dot diagrams and VSEPR theory predict the shapes of the following molecules. Show the
valence electron count and account for all electrons. Indicate the number of bonding pairs and lone
pairs of electrons. Draw the 3-D representation of the molecules.
a. NF3 5+ 3(7) = 26 – 6 = 20
3 bonding / 1 lone = trigonal pyramidal
b. PI5
5+ 5(7) = 40 – 10 = 30
5 bonding / 0 lone = trigonal bipyramidal
15. Explain the difference between polar covalent bonds, non-polar covalent bonds, ionic bonds and
coordinate covalent bonds.
Polar – unequal sharing of bonding electrons results in +/- dipoles in compound.
NP – equal sharing of bonding electrons results in neutral compound.
I – transfer of electrons between metal and nonmetal resulting in +/- ions which attract.
CC – covalent bond where both electrons of a single bond are donated by one element in the bond.
Mr. Storie
KINETICS PROBLEMS
40S Chemistry
Final Exam Review
9. The reaction, A + 2B  Products, was found to have the rate law, Rate = k[A][B]2. While holding the
concentration of A constant, the concentration of B was increased from x to 3x. Predict by what factor
the rate of the reaction will increase.
Rate α [A][B]2
1x α [1][1]2
9x α [1][3]2
10. For the hypothetical reaction A + B  Products, the following initial rates of reaction have been
measured for the given reactant concentrations.
Experiment
1
2
3
a.
b.
c.
d.
e.
[A] (M)
0.010
0.015
0.010
[B] (M)
0.020
0.020
0.010
Rate (mol/(L∙hr))
0.020
0.030
0.005
Calculate the order for reactant A. Trial1/2 = 1st
Calculate the order for reactant B. Trial3/1 = 2nd
Calculate the overall order for the reaction. 3rd order overall
Write the rate law expression. Rate = k[A][B]2
Solve for the specific rate constant, k. 5000
11. For a reaction with the rate law - rate = k [A]n [B]m - Determine the factor by which the rate changes if
both [A] and [B] are doubled given the following values of “n” and “m”. Show all your work.
a. n=0, m=2
Rate α [A]0[B]2
1x α [1]2
4x α [2]2
b. n=2, m=2
Rate α [A]2[B]2
1x α [1]2[1]2
16x α [2]2[2]2
c. n=1, m=3
Rate α [A][B]3
1x α [1][1]3
16x α [2][2]3
12. For the chemical reaction H2O2 + 2H+ + 2I-  I2 + 2H2O
the rate law expression is Rate = k[H2O2][I-]. The following mechanism has been suggested.
H2O2 + I-  HOI + OHOH- + H+  H2O
HOI + H+ + I-  I2 + H2O
a. Define the term “intermediate” and identify all intermediates included in this reaction.
b. Determine which of the steps is the RDS, and explain how the conclusion was reached.
a. compound that in is a product in one step and a reactant in a following step.
b. First step is the RDS – rate law for the overall reaction is the rate law for the RDS
Mr. Storie
40S Chemistry
Final Exam Review
13. Draw a Potential Energy Diagram for the following exothermic reaction:
2 SO2 (g) + O2 (g)  2 SO3 (g) ΔH° = -198 kJ
Label your diagram with the following information:
a. reactants (write the actual reactants)
b. products (write the actual products)
c. activated complex
d. activation energy
e. ΔH° = -198 kJ
14. If ammonia gas, NH3, reacts at a rate of 0.090 mol/Ls according to the reaction
4 NH3 (g) + 5 O2 (g)  4 NO (g) + 6 H2O (g)
a. At what rate does oxygen gas react under the same conditions? 0.11 mol/Ls
b. What is the rate of formation of water? 0.14 mol/Ls
c. What is the rate of production of nitrogen monoxide? 0.090 mol/Ls
15. The reaction
A + B + C  E + F + G
Trial
[A]
(mol/L)
1
1.0
2
2.0
3
1.0
4
1.0
5
1.5
was studied at 0°C and the following data was collected:
[B]
[C]
Initial Rate
(mol/L)
(mol/L)
(mol/L•s)
2.0
2.0
1.66
2.0
2.0
3.33
4.0
2.0
1.66
2.0
4.0
6.65
5.0
?
7.25
a. What is the rate law for this reaction? Rate = k[A][C]2
b. What is the value of the rate constant 0.42
c. What is the rate if [A] = 1.5 mol/L, [B] = 2.5 mol/L, [C] = 0.25 mol/L? 0.039 mol/Ls
d. What is the [C] in trial 5? 3.4 mol/L
Mr. Storie
40S Chemistry
16. Write the rate laws for the following elementary reactions
a. N2 (g) + 3 H2 (g)  2 NH3 (g)
b. N2 (g) + 2 O2 (g)  2 NO2 (g)
c. H2 (g) + Cl2 (g)  2 HCl (g)
Final Exam Review
Rate = k[N2][H2]3
Rate = k[N2]O2]2
Rate = k[H2][Cl2]
Determine the value of k in 8(a), when [N2] = 0.50 mol/L and
[H2] = 1.5 mol/L and NH3 is produced at a rate of 2.5 mol/Ls.
1.5
EQUILIBRIUM PROBLEMS
6. At 773 K, the reaction
2 NO (g) + O2 (g)  2 NO2 (g)
produces the following concentrations:
[NO] = 3.49 X 10-4M; [O2] = 0.80M; [NO2] = 0.25M.
a. What is the equilibrium constant expression for this reaction? Kc = [NO]2/[NO]2[O2]
b. What is the equilibrium constant for the reaction? 6.4 x 105
7. Phosphorous pentachloride decomposes to phosphorous trichloride according to this equation:
PCl5 (g)  PCl3 (g) + Cl2 (g)
Keq = 1.00 x 10-3
At equilibrium, [PCl5] = 1.00M and [Cl2] = 3.16 x 10-2M.
a. Calculate the concentration of PCl3. 3.16 x 10-2 M
b. Chlorine gas, Cl2 (g) is toxic. If we could manipulate the pressure of the container for this
reaction, how can we minimize the formation of this gas? Explain using your knowledge of Le
Chatelier’s principles.
Increase the pressure – system will work to decrease the pressure by reducing the number of
particles present in the container – shift left to use 2 products to make 1 reactant.
8. Consider the reaction:
2 HBr (g)  H2 (g) + Br2 (g)
Initially, 0.25 mol of hydrogen and 0.25 mol of bromine are placed in 500 mL reaction vessel and
heated. The Kc for the reaction is 0.020. Calculate the concentrations at equilibrium.
Type IV –ice table, solve for x - 0.78 M, 0.11 M, 0.11 M
9. For the given reaction of methanol, the equilibrium concentrations were found to be [CO] = 0.170 M, [H 2]
= 0.322, [CH3OH] = 0.0406. Find the value of Kc.
CH3OH (g)  CO (g) + 2 H2 (g)
Type I – plug and solve - 0.434
Mr. Storie
40S Chemistry
Final Exam Review
10. Hydrogen peroxide can be decomposed as follows:
H2O2 (l)  H2 (g) + O2 (g)
(endothermic)
Equilibrium is established in a 10 L flask at room temperature. Predict the direction of the
equilibrium shift.
d. hydrogen gas is added to the flask.
Shift left to reduce pressure / decrease concentration.
e. The temperature is raised to 500 ºC.
Shift right to reduce temperature (favours endo rxn)
f. The entire mixture is compressed into a smaller volume. Shift left to decrease pressure (too a
point, can’t compress liquid)
ACIDS AND BASES PROBLEMS
11. You have water at 25o to which you add 0.050 M NaOH.
Complete the chart:
[H3O+]
Before adding NaOH
1.0 x 10-7 M
After adding NaOH
2.0 x 10-13 M
Strong base
Use Kw to find H3O+
[OH-]
1.0 x 10-7 M
0.05 M
12. This time with a weak base. Let’s add 0.0050 M NH4OH. Kb =1.77x 10-5.
Before adding NH4OH
After adding NH4OH
[H3O+]
1.0 x 10-7 M
3.3 x 10-11 M
[OH-]
1.0 x 10-7 M
3.0 x 10-4 M
Weak base – use ice table, find x.
Use Kw to find H3O+
13. If an acid has a hydronium concentration of 0.000036 M, what is the pOH of the solution?
pH = -log[0.000036]
= 4.4
pOH = 14-4.4 = 9.6
14. What is the hydroxide ion concentration of a solution with a pH of 4.9?
pOH = 14-4.9 = 9.1
[OH-] = 10-9.1 = 8.0 x 10-10 M
15. What is the % ionization of a 2.5 M solution of acetic acid (Ka = 1.76 x 10-5).
Weak acid – ice table, find x.
√(1.76 x 10-5)(2.5) = x
x = [H+] = 0.0066 M
PD = (0.0066 / 2.5) x 100% = 0.27%
Mr. Storie
40S Chemistry
16. The pH of 0.50M HNO2 is 4.85. Find Ka.
[H+] = 10-4.85 = 1.4 x 10-5 M
Ka = P/R = (1.4 x 10-5)2 / 0.50 = 3.9 x 10-10
Final Exam Review
17. What is the concentration of phosphoric acid if 15.0 ml of the solution is neutralized by 38.5 mL of a 0.15
M NaOH solution?
3 NaOH + H3PO4  Na3PO4 + 3 H2O
(0.15 mol/L)(0.0385 L) = 0.00578 mol base x 1 acid/3 base = 0.00193 mol acid
0.00193 mol / 0.015 L = 0.128 M
18. Suppose 3.5% of a weak solution of 0.020 M monoprotic acid is ionized. Calculate the Ka.
[H+] = (3.5%)(0.02) / 100 = 0.0007 M
Ka = (0.0007)2 / 0.02 = 2.45 x 10-5
19. Complete and balanced the following reactions:
d. Sulphuric acid plus potassium hydroxide 
H2SO4 + 2 KOH K2SO4 + 2 H2O
e. Phosphoric acid + Ca(OH)2 
2 H3PO4 + 3 Ca(OH)2  Ca3(PO4)2 + 6 H2O
f. Nitric acid and magnesium hydroxide 
2 HNO3 + Mg(OH)2  Mg(NO3)2 + 2 H2O
20. A solution was made by dissolving 28.5 g of KOH in 0.50 L of water. If 0.250 L of this solution was
titrated with 0.136 L of H2SO4, what is the molarity of the acid? 0.938 M
2 KOH + H2SO4  K2SO4 + 2 H2O
28.5 g x 1mol / 56g = 0.509 mol / 0.5L = 1.02 M x 0.25 L = 0.255 mol base
0.255 mol base x 1acid/2base = 0.127 mol acid
0.127 mol acid / 0.136 L = 0.934 M acid
ELECTROCHEMISTRY
15. Consider the particles:
Na+, Mg, Cl-, F2, H2O
a) Which can be oxidized? Mg, Cl-, H2O
b) Which can be reduced? Na+, F2, H2O
c) Which is the best reducing agent? Na+
16. For each of the following cells (which may or may not be written according to the standard line notation)
indicate which half-cell is the anode and which is the cathode.
a) Zn│Zn2+║Cu2+│Cu
Anode: Zn Cathode: Cu
+
2+
b) Ag│Ag ║Ni │Ni
Anode: Ni
Cathode: Ag
c) Sn│Sn2+║Au3+│Au
Anode: Sn Cathode: Au
Mr. Storie
40S Chemistry
Final Exam Review
17. Sketch a galvanic cell between copper and barium. Show the direction of electron flow and ion migration,
identify the anode and cathode, the species present in each half-cell, indicate the voltage on a voltmeter,
and label the electrodes. Also show the half-reactions, overall cell reaction and the Emf calculation.
+ 3.24 V
K+ NO3-
Anode
Ba
Cu
Cathode
Ba 2+
NO3-
Cu2+
NO3-
Cathode reaction: Cu2+ + 2e-  Cu(s)
Anode reaction: Ba(s)  Ba2+ + 2eOverall reaction: Ba(s) + Cu2+  Ba2+ + Cu(s)
What is the cell voltage? 2.90 + 0.34 = + 3.24 V
18. For each of the following cells write half-reactions, give the balanced net cell reaction, and calculate the
Emf of the cell.
a) Al3+(aq) + Mg(s) → Al(s) + Mg2+(aq)
b) Cr(s)│Cr3+(aq) (1.0 mol/L)║Ag+(aq) (1.0 mol/L)│Ag(s)
a) 2 Al3+(aq) + 3 Mg(s) → 2 Al(s) + 3 Mg2+(aq)
Ecell = 2.37 + (-1.66) = + 0.71 V
b) Cr(s) + 3 Ag1+ (aq) → Cr3+ (aq) + 3 Ag (s)
Ecell = 0.74 + 0.80 = + 1.54 V
19. Write out anode and cathode reactions for the electrolysis of the following.
a) CaCl2(l)
b) CuI2(l)
a) Anode (O): 2 Cl-  Cl2 (g) + 2 eCathode (R): Ca2+ + 2e-  Ca(s)
b) Anode (O): 2 I-  I2 (g) + 2 eCathode (R): Cu2+ + 2e-  Cu(s)
20. How many coulombs of charge must pass through a cell in order to deposit 9.45 g of zinc from a solution
of zinc nitrate?
Zn2+ + 2 e-  Zn (s)
9.45 g x 1 mol/65 g x 2 e- / 1 Zn = 0.291 mol e0.291 mol e- x 96500 C/1 mol = 28100 C
Mr. Storie
40S Chemistry
Final Exam Review
21. What happens in an oxidation reaction in terms of electrons?
Oxidation reaction has an atom losing electrons to form an ion.
22. What happens in a reduction reaction in terms of electrons?
Reduction reaction has an ion gaining electrons to form an atom.
23. Assign oxidation numbers to each atom in the following compounds.
+1 +5 -2
+1 +5 -2
a) H3SO4
b. HNO3
24. Which reactant in the following reaction is oxidized and which is the oxidizing agent?
+2
+2
+4
0
CO(g) + PbO(s) → CO2(g) + Pb(s)
O: C
R: Pb
OA: PbO
RA: CO
25. Balance the following equation using the oxidation number method.
-1
+5
0
5 HBr + 1 HBrO3 → 3 Br2 + 3 H2O
26. Balance the following equations in acid or base as indicated in brackets.
a. Cu + HNO3 → Cu2+ + NO2 + H2O
(acid)
b. N2O4 + Br → NO2 + BrO3
(base)
a)
b)
O:
R:
2x(
O:
R:
2H+ +
Cu  Cu2+ + 2eHNO3 + 1e-  NO2 + H2O )
H+ +
Cu  Cu2+ + 2e2 HNO3 + 2 e-  2 NO2 + 2 H2O
NET:
2H+ + 2 HNO3 + Cu  2 NO2 + Cu2+ + 2 H2O
O:
R:
6 OH- + 3 H2O + Br-  BrO3- + 6e- + 6 H+ + 6 OH3x ( N2O4 + 2e-  2 NO2- )
O:
R:
6 OH- + 3 H2O + Br-  BrO3- + 6e- + 6 H+ + 6 OH3 N2O4 + 6e-  6 NO2-
NET:
6 OH- + 3 N2O4 + Br-  BrO3- + 6 NO2- + 3 H2O
Mr. Storie
40S Chemistry
27. Examine the cell below and answer the questions that follow.
Final Exam Review
+ 0.94 V
Anode
Cathode
K+ NO3-
Sn
Ag
Ag +
NO3-
a)
b)
c)
d)
e)
f)
g)
h)
Sn2+
NO3-
Cathode reaction:
Ag+ + 1e-  Ag(s)
Anode reaction:
Sn(s)  Sn2+ + 2eOverall reaction:
2 Ag+ + Sn(s)  2 Ag(s) + Sn2+
What is the cell voltage? Ecell = 0.14 + 0.80 = + 0.94 V
Label anode and cathode.
Indicate the direction of travel of ions and electrons.
While the cell operates which electrode gains in mass? Cathode
While the cell operates which electrode decreases in mass? Anode