Mr. Dehne AP Chem
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Date: __________________
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AP Chem
Types of Chemical Reactions and Solution Stoichiometry
Topic #4
Reactions/Solution Stoich WS#1 (Aqueous Solutions: Strong and Weak Electrolytes/Solution Concentration: Molarity (5pts))
1. Show how each of the following strong electrolytes “breaks up” into component ions upon dissolving in water by drawing
molecular level pictures.
a. NaBr
f. FeSO4
b. MgCl2
g. KMnO4
c. Al(NO3)3
h. HClO4
d. (NH4)2SO4
i. NH4C2H3O2 (ammonium acetate)
e. NaOH
2. Calcium chloride is a strong electrolyte and is used to “salt” streets in the winter to melt ice and snow. Write a reaction to
show how this substance breaks apart when dissolved in water.
3. Calculate the molarity of each of these solutions.
a. A 5.623g sample of NaHCO3 is dissolved in enough water to make 250.0mL solution.
b. A 184.6g sample of K2Cr2O7 is dissolved in enough water to make 500.0mL solution.
c. A 0.1025g sample of copper metal dissolved in 35mL of concentrated HNO3 to form Cu2+ ions and then water is
added to make a total volume of 200.0mL. (Calculate the molarity of Cu 2+.)
4. Calculate the concentration of all ions present in each of the following solutions of strong electrolytes.
a. 0.100mol of Ca(NO3)3 in 100.0mL of solution.
b. 2.5mol of Na2SO4 in 1.25L of solution.
c. 5.00g of NH4Cl in 500.0mL of solution.
d. 1.00g K3PO4 in 250.0mL of solution.
5. Which of the following solutions of strong electrolytes contains the largest number of moles of chloride ions: 100.0mL of
0.30M AlCl3, 50.0mL of 0.60M MgCl2, or 200.0mL of 0.40M NaCl?
6. What volume of a 0.100M solution of NaHCO3 contains 0.350g of NaHCO3?
7. Describe how you would prepare 2.00L of each of the following solutions.
a. 0.250M NaOH from solid NaOH
b. 0.250M NaOH from 1.00M NaOH stock solution
c. 0.100M K2CrO4 from solid K2CrO4
d. 0.100M K2CrO4 from 1.75M K2CrO4 stock solution
8. A solution is prepared by dissolving 10.8g ammonium sulfate in enough water to make 100.0mL of stock solution. A
10.00mL sample of this stock solution is added to 50.00mL of water. Calculate the concentration of ammonium ions and
sulfate ions in the final solution.
9. A standard solution is prepared for the analysis of fluoxymesterone (C 20H29FO3), an anabolic steroid. A stock solution is first
prepared by dissolving 10.0mg of fluoxymesterone in enough water to give a total volume of 500.0mL. A 100.0μL aliquot
(portion) of this solution is diluted to a final volume of 100.0mL. Calculate the concentration of the final solution.
Reactions/Solution Stoich WS#2 (Precipitation/Acid-Base/Oxidation-Reduction Reactions)
Part#1: Precipitation Reactions (3pts)
1. When the following solutions are mixed together, what precipitate (if any) will form?
a. BaCl2(aq) + Na2SO4(aq)
e. FeSO4(aq) + KCl(aq)
b. Pb(NO3)2(aq) + KCl(aq)
f. Al(NO3)3(aq) + Ba(OH)2 (aq)
c. AgNO3(aq) + Na3PO4(aq)
g. CaCl2(aq) + Na2SO4(aq)
d. NaOH(aq) + Fe(NO3)3(aq)
h. K2S(aq) + Ni(NO3)2(aq)
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8.
For the reactions in Exercise 1, write the balanced molecular equation, complete ionic equation, and net ionic equation. If no
precipitate forms, write “No reaction.”
Give an example how each of the following could be produced using a precipitation reaction. Write the balanced molecular
equation for each reaction.
a. Fe(OH)3(s)
(c) PbSO4(s)
b. Hg2Cl2(s)
(d) BaCrO4(s)
Write net ionic equations for the reaction, if any, that occurs when aqueous solutions of the following are mixed.
a. ammonium sulfate and barium nitrate
b. lead (II) nitrate and sodium chloride
c. sodium phosphate and potassium nitrate
d. sodium bromide and rubidium chloride
e. copper (II) chloride and sodium hydroxide
f. chromium (III) chloride and sodium hydroxide
g. silver nitrate and ammonium carbonate
h. copper (II) sulfate and mercury (I) nitrate
i. strontium nitrate and potassium iodide
A lake may be polluted with Pb2+ ions. What precipitation reaction might you use to test for the presence of Pb 2+?
What mass of Na2CrO4 is required to precipitate all of the silver ions from 75.0mL of a 0.100M solution of AgNO3?
What mass of solid aluminum hydroxide can be produced when 50.0mL of 0.200M Al(NO3)3 is added to 200.0mL of 0.100M
KOH?
How many grams of silver chloride can be prepared by the reaction of 100.0mL of 0.20M silver nitrate with 100.0mL of
0.15M calcium chloride? Calculate the concentrations of each ion remaining after the precipitation is complete.
Part 2: Acid-Base Reactions (3pts)
9. Write the balanced molecular, complete ionic, and net ionic equations for each of the following acid-base reactions.
a. HClO4(aq) + Mg(OH)2(s) 
b. HCN(aq) + NaOH(aq) 
c. HCl(aq) + NaOH(aq)
d. HNO3(aq) + Al(OH)3(s) 
e. HC2H3O2(aq) + KOH(aq) 
f. Ca(OH)2(aq) + HCl(aq) 
10. Write the balanced molecular, complete ionic, and net ionic equations for the reactions that occur when the following are
mixed.
a. potassium hydroxide (aq) and nitric acid
b. barium hydroxide (aq) and hydrochloric acid
c. perchloric acid and solid iron (III) hydroxide
11. What volume of each of the following acids will react completely with 50.00mL of 0.200M NaOH?
a. 0.100M HCl
b. 0.150M HNO3
c. 0.200 M HC2H3O2 (1 acidic hydrogen)
12. What volume of each of the following bases will react completely with 25.00mL of 0.200M HCl?
a. 0.100M NaOH
b. 0.0500M Ba(OH)2
c. 0.250M KOH
13. A solution is prepared by dissolving 15.0g NaOH in 150.0mL of 0.250M nitric acid. Will the final solution be acidic, basic or
neutral? Calculate the concentrations of all the ions in solution after the reaction has occurred. Assume no volume change on
addition of NaOH.
14. A 25.00mL sample of hydrochloric acid solution requires 24.16mL of 0.106M sodium hydroxide for complete neutralization.
What is the concentration of the original hydrochloric acid solution?
15. A student titrates an unknown amount of potassium hydrogen phthalate (KHC 8H4O4, often abbreviated KHP) with 20.46mL
of a 0.2000M NaOH solution. KHP (MM = 204.22g/mol) has one acidic hydrogen. How many grams of KHP were titrated
(reacted completely) by the sodium hydroxide solution?
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Part 3: Oxidation-Reduction Reactions (3pts)
16. Assign oxidation numbers for all the atoms in each of the following compounds.
a. KMnO4
k. Fe3O4
b. NiO2
l. XeOF4
c. K4Fe(CN)6 (Fe only)
m. SF4
d. (NH4)2HPO4
n. CO
e. P4O6
o. Na2C2O4
f. UO22+
p. Mg2P2O7
g. As2O3
q. Na2S2O3
h. NaBiO3
r. Hg2Cl2
i. As4
s. Ca(NO3)2
j. HAsO2
17. Assign the oxidation state for bromine in each of the following compounds.
a. HBr
d. HBrO4
b. HOBr
e. BrF3
c. Br2
18. Specify which of the following are oxidation-reduction reactions, and identify the oxidizing agent, the reducing agent, the
substance being oxidized, and the substance being reduced.
a. CH4(g) + 2O2(g)  CO2(g) + 2H2O(g)
b. Zn(s) + 2HCl(aq)  ZnCl2(aq) + H2(g)
c. Cr2O72-(aq) + 2OH-(aq)  2CrO42-(aq) + H2O(l)
d. O3(g) + NO(g)  O2(g) + NO2(g)
e. 2H2O2(l)  2H2O(l) + O2(g)
f. 2CuCl(aq)  CuCl2(aq) + Cu(s)
19. Balance the following oxidation-reduction reactions that occur in acidic solution.
a. Zn(s) + HCl(aq)  Zn+(aq) + H2(g) + Cl-(aq)
b. I-(aq) ClO-(aq)  I3-(aq) + Cl-(aq)
c. As2O3(s) + NO3-(aq)  H3AsO4(aq) + NO(g)
d. Br-(aq) + MnO4-(aq)  Br2(l) + Mn2+(aq)
e. CH3OH(aq) + Cr2O72-(aq)  CH2O(aq) + Cr3+(aq)
20. Balance the following oxidation-reduction reactions that occur in basic solution.
a. Al(s) + MnO4-(aq)  MnO2(s) + Al(OH)4-(aq)
b. Cl2(g)  Cl-(aq) + OCl-(aq)
c. NO2-(aq) + Al(s)  NH3(g) + AlO2-(aq)
21. Chlorine gas was first prepared in 1774 by C.W. Scheele by oxidizing sodium chloride with manganese (IV) oxide. The
reaction is
NaCl(aq) + H2SO4(aq) + MnO2(s)  Na2SO4(aq) + MnCl2(aq) + H2O(l) + Cl2(g)
Balance this equation.
Reactions/Solution Stoich WS#3 (Conceptual Problems (5pts))
1. Calcium metal will react with water as follows: Ca(s) + 2H2O(l)  Ca(OH)2(aq) + H2(g). What is the molarity of hydroxide
ions in the solution formed when 0.100g calcium metal is dissolved in enough water to make a final volume of 450.mL?
2. Using the general solubility rules given in the notes, name three reagents that would form precipitates with each of the
following ions in aqueous solution. Write the net ionic equation for each of your suggestions.
a. chloride ion
d. sulfate ion
b. calcium ion
e. mercury (I) ion Hg22+
c. iron (III) ion
f. silver ion
3. During the developing process of black-and-white film, silver bromide is removed from photographic film by the fixer. The
major component of the fixer is sodium thiosulfate. The net ionic equation for the reaction is
AgBr(s) + 2S2O32-(aq)  Ag(S2O3)23-(aq) + Br-(aq)
What mass of AgBr can be dissolved by 1.00L of 0.200M Na2S2O3?
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8.
Saccharin (C7H5NO3S) is sometimes dispensed in tablet form. Ten tablets with a total mass of 0.5894g were dissolved in
water. They were oxidized to convert all of the sulfur to sulfate ion, which was precipitated by adding an excess of barium
chloride solution. The mass of BaSO4 obtained was 0.5032g. What is the average mass of saccharin per tablet? What is the
average mass percent of saccharin in the tablets?
A student added 50.0mL of NaOH solution to 100.0mL of 0.400M HCl. The solution was then treated with an excess of
aqueous chromium (III) nitrate, resulting in formation of 2.06g of precipitate. Determine the concentration of the NaOH
solution?
A 10.00mL sample of vinegar, an aqueous solution of acetic acid (HC 2H3O2), is titrated with 0.5062M NaOH, and 16.58mL
is required to react to reach the equivalence point.
a. What is the molarity of the acetic acid?
b. If the density of the vinegar is 1.006g/cm3, what is the mass percent of acetic acid in the vinegar?
A 2.20g sample of an unknown acid (empirical formula = C 3H4O3) is dissolved in 1.0L of water. A titration required 25.0mL
of 0.500M NaOH to react completely with all the acid present. Assuming the unknown acid has one acidic proton per
molecule, what is the molecular formula of the unknown acid?
One of the classical methods for the determination of the manganese content in steel is to convert all the manganese to the
deeply colored permanganate ion and then to measure the absorption of light. The steel is dissolved in nitric acid, producing
the manganese (II) ion and nitrogen dioxide gas. This solution is then reacted with an acidic solution containing periodate
ion; the products are the permanganate iodate ions. Write balanced equations for both these steps.
Extra Credit Problems (+2pts/question, 12 pts possible). Answers must be correct with work legible and coherent. No teacher help.
1. In most ionic compounds, cobalt is either Co (II) or Co (III). One such compound, containing chloride ion and waters of
hydration, was analyzed, and the following results were obtained. A 0.256g sample of the compound was dissolved in water,
and excess silver nitrate was added. The silver chloride was filtered, dried, and weighed, and it had a mass of 0.308g. A
second sample of 0.416g of the compound was dissolved in water, and an excess of sodium hydroxide was added. The
hydroxide salt was filtered and heated in a flame, forming cobalt (III) oxide. The mass of cobalt (III) oxide formed was
0.145g.
a. What is the percent composition, by mass, of the compound?
b. Assuming the compound contains one cobalt atom per formula unit, what is the molecular formula?
c. Write balanced equations for the three reactions described.
2. You have two 500.0mL aqueous solutions. Solution A is a solution of silver nitrate, and solution B is a solution of potassium
chromate. The masses of the solutes in each of the solutions are the same. When the solutions are added together a blood-red
precipitate forms. After the reaction has gone to completion, you dry the solid and find that it has a mass of 331.8g.
a. Calculate the concentration of the potassium ions in the original potassium chromate solution.
b. Calculate the concentration of the chromate ions in the final solutions.
3. You are given a solid that has a mixture of Na2SO4 and K2SO4. A 0.205g sample of the mixture is dissolved in water. An
excess of an aqueous solution of BaCl2 is added. The BaSO4 that is formed is filtered, dried, and weighed. Its mass is 0.298g.
What is the mass percent of SO42- ion in the sample? What are the percent compositions by mass of Na 2SO4 and K2SO4 in the
sample?
4. What volume of 0.0521M Ba(OH)2 is required to neutralize exactly 14.29mL of 0.141M H3PO4? Phosphoric acid contains
three acidic hydrogens.
5. Some of the substances commonly used in stomach antacids are MgO, Mg(OH) 2, and Al(OH)3.
a. Write a balanced equation for the neutralization of hydrochloric acid by each of the substances.
b. Which of these substances will neutralize the greatest amount of 0.10M HCl per gram?
6. Citric acid, which can be obtained from lemon juice, has the molecular formula C 6H8O7. A 0.250g sample of citric acid
dissolved in 25.0mL of water requires 37.2mL of 0.105M NaOH for complete neutralization. How many acidic hydrogens
per molecule does citric acid have?
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Answer Key
WS#1
1. NA
2. CaCl2(s)  Ca2+(aq)+ 2Cl-(aq)
3. (a) 0.2677M
(b) 1.255x10-3M
(c) 8.065x10-3M
4. (a) [Ca2+] = 1.00M/[NO3-] =2.00M (b) [Na+]=4.0M/[SO42-]=2.0M (c) [NH4+]=[Cl-]=0.187M (d)[K+]=0.0565M/[PO43-]=0.0188M
5. 100.0mL of 0.30M AlCl3
6. 41.7mL NaHCO3
7. Description
8. [NH4+] = 0.272M and [SO42-] = 0.136M
9. [C20H29FO3] = 5.944x10-8M
WS#2
Part 1
1. (a) BaSO4(s) (b) PbCl2(s) (c) Ag3PO4(s) (d) Fe(OH)3(s) (e) NR (f) Al(OH)3(s) (g) CaSO4(s) (h) NiS(s)
2. Do in class.
3.
a. Fe(NO3)3 + NaOH 
b. Hg2(NO3)2 + KCl 
c. Pb(NO3)2 + Rb2SO4 
d. BaCl2 + Li2CrO4 
4.
a. SO42-(aq) + Ba2+(aq)  BaSO4(s)
b. Pb2+(aq) + 2Cl-(aq)  PbCl2(s)
c. NR
d. NR
e. Cu2+(aq) + 2OH-(aq)  Cu(OH)2(s)
f. Cr3+(aq) + 3OH-(aq)  Cr(OH)3(s)
g. 2Ag+(aq) CO32-(aq)  Ag2CO3(s)
h. SO42-(aq) + Hg22+(aq)  Hg2SO4(s)
i.
NR
5. Na2SO4, K2CrO4, etc.
6. 0.607g
7. 0.520g Al(OH)3
Part 2
8. 2.9g AgCl; 0M of Ag+; 0.10M NO3-; 0.075 M Ca2+; 0.050M Cl9.
a. 2H+(aq) + Mg(OH)2(s)  2HOH(l) + Mg2+(aq)
b. HCN(aq) + OH-(aq)  HOH(l) + CN-(aq)
c. H+(aq) + OH-(aq)  HOH(l)
d. 3H+(aq) + Al(OH)3(s)  3HOH(l) + Al3+(aq)
e. HC2H3O2(aq) + OH-(aq)  HOH + C2H3O2-(aq)
f. 2OH-(aq) + 2H+(aq)  2HOH(l)
10.
a. OH-(aq) + H+(aq)  HOH(l)
b. 2OH-(aq) + 2H+(aq)  2HOH
c. 3H+(aq) + Fe(OH)3(s)  3HOH(l) + Fe3+(aq)
11. (a) 100mL
(b) 66.7mL
(c) 50.0mL
12. (a) 50mL
(b) 100mL
(c) 20mL
13. Basic, 0.250M NO3-;
2.50M Na+;
2.25M OH14. 0.102M
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15. 0.4178g
Part 3
16.
WS#3
1.
2.
3.
4.
5.
6.
7.
8.
0.0111M
(a) AgNO3, Pb(NO3)2, and Hg2(NO3)2 would form ppt with Cl- ions.
(b) Na2SO4, Na2CO3, and Na3PO4 would form ppt
with Ca2+ ions. (c) NaOH, Nas2S, and Na3PO4 would form ppt with Fe3+
(d) BaCl2, Pb(NO3)2, and Ca(NO3)2 would
form ppt with SO42- ion
18.8g
39.49mg/tablet; 67.00%
2.00M
(a) 0.8393M
(b) 5.010%
C6H8O6
2H+(aq) + Mn(s) +2HNO3(aq) → Mn2+(aq) + 2NO2(g) + 2H2O(l)
3H2O(l) + 2Mn2+(aq) + 5IO4-(aq) → 2MnO4-(aq) + 5IO3-(aq) + 6H+(aq)
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