Download 1aUnit Two Handouts - Dunmore High School

Las Positas College
Chem 30A, 31
JB—6/17/02
WORKSHEET: Net Ionic Equations
The key to writing correct net ionic equations is in knowing which substances to rewrite
as ions and which substances to leave unchanged.
Strong electrolytes exist in solution as ions and must always be written as ions for
reactions in solution
Strong Electrolytes:
strong acids
strong bases
soluble salts
Weak and non electrolytes exist predominantly as molecules or formula units in solution
and must never be broken up when writing equations for reactions in solution.
Weak Electrolytes:
weak acids
weak basess
Non Electrolytes:
insoluble salts and bases
gases
metals
diatomic molecules
all others not described above
Decision Tree Practice:
Identify each of the following substances as strong acid, weak acid, strong base, weak
base, insoluble base, soluble salt, insoluble salt, molecular liquid, molecular gas, or
insoluble element. Then write each substance as ions or not as ions in accordance with the
decision tree.
Ba(OH)2
CuCl2
NH3
H2SO4
H2
KCl
HC2H3O2
Cu(NO3)2
BaSO4
Pb(NO3)2
Pb(NO2)2
H2O
AgBr
MgBr2
MgCO3
CuS
CO2
HBr
HF
Al
H3PO4
H2S
LiHCO3
Fe(OH)3
CaSO4
Fe(C2H3O2)2
K2SO4
HNO3
H2CO3
ZnS
NOTE: When H2CO3, H2SO3 or NH4OH are formed as products, they do break down,
though not into ions. They break down into H2O and a gaseous substance.
For each of the following, write the molecular equation (balanced, of course), the total
ionic equation (still balanced), and the net ionic equation (also balanced). If examination
of the total ionic equation reveals that there is no net reaction, then for the net ionic
equation write the words “No Reaction.”
1.
Aluminum metal is added to nitric acid solution. (single replacement)
2.
A lead (II) nitrate solution is added to a calcium acetate solution. (double
replacement)
3.
A sulfuric acid solution is added to a solution of potassium hydrogen carbonate.
(double replacement)
4.
A barium nitrate solution is added to a sodium sulfate solution. (double replacement)
5.
A sodium hydroxide solution is added to a phosphoric acid solution. Assume that 2
of the hydrogens in phosphoric acid react.
Las Positas College
Chemistry 30A, 31
JB—7/30/01
DECISION TREE: Should a formula be written as ions?
Is the substance an acid (formula begins with H), a base (contains hydroxide ion), a salt
(cation anion) or other?
If it is an acid, go to A.
If it is a base, go to B.
If it is a salt, go to S.
If it is an other, do not write it as ions.
Example: Zn stays Zn
(Note: There are three substances that decompose yielding gases when
formed in chemical reactions: H2CO3, H2SO3 and NH4OH.)
A.
Is it a strong acid: H2SO4(aq), HClO4(aq), HNO3(aq), HCl(aq), HBr(aq), or
HI(aq)?
If yes, write it as ions. Example: H2SO4(aq) becomes 2 H+ + SO42If no, do not write it as ions. Example: HNO2(aq) stays HNO2
B.
Is it a strong base: NaOH, LiOH, KOH, Ba(OH)2, or Ca(OH)2?
If yes, write it as ions. Example: NaOH becomes Na+ + OHIf no, do not write it as ions. Example: Fe(OH)3 stays Fe(OH)3
(Note: Most hydroxides not listed above are weak or nonelectrolytes because they
are insoluble in water—always check this out when writing net ionic equations.)
S.
Is it a soluble salt? Consult a table of solubilities.
If soluble, write it as ions.
Example: MgCl2 becomes Mg2+ + 2 Cl-
If not soluble, do not write it as ions.
Example: AgCl stays AgCl(s)
© Adrian Dingle’s Chemistry Pages 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012. All rights reserved.
These materials may NOT be copied or redistributed in any way, except for individual class instruction.
Revised August 2011
AP WORKSHEET 12a: ANSWERS
1. A solution of potassium permanganate is added to a solution of conc. hydrochloric acid.
2MnO4- + 16H+ + 10Cl-  8H2O + 5Cl2 + 2Mn2+
ANSWER: Chloride ions lose electrons
2. A solution containing iodide ions is added to a solution containing iron (III) ions.
2I- + 2Fe3+  2Fe2+ + I2
ANSWER: Fluorine since it most readily accepts electrons
3. Phosphorous trichloride is added to water.
PCl3 + 3H2O  H3PO3 + 3H+ + 3ClANSWER: Less than 7 since acids are formed
4. Lithium metal is burned in air.
4Li + O2  2Li2O
0
ANSWER: Li  Li
+
5. A solution of potassium dichromate is added to an acidified solution of sodium sulfite.
Cr2O72- + 8H+ + 3SO32- 3SO42- + 4H2O + 2Cr3+
ANSWER: Orange Cr
6+
forms green Cr
3+
6. A solution of tin (II) sulfate is added to a solution of iron (III) sulfate.
Sn2+ + 2Fe3+  2Fe2+ + Sn4+
ANSWER: Brown Fe
3+
forms green Fe
2+
7. A solution of calcium hydroxide is added to a solution of magnesium chloride.
Mg2+ + 2OH-  Mg(OH)2
ANSWER: Calcium and chloride ions
8. Propane is burned completely in air.
C3H8 + 5O2  3CO2 + 4H2O
ANSWER: Alkanes
9. Manganese (IV) oxide is added to a solution of hydrobromic acid.
MnO2 + 4H+ + 2Br-  Br2 + 2H2O + Mn2+
0
ANSWER: [Ar]4s 3d
5
10. Small chunks of solid sodium are added to water.
2Na + 2H2O  2Na+ + 2OH- + H2
ANSWER: The sodium would float on the surface with effervescence. The gas may ignite
C:\Users\Adrian\Dropbox\ADCP\apwsheet12aanswers.doc
Page 1 of 2
© Adrian Dingle’s Chemistry Pages 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012. All rights reserved.
These materials may NOT be copied or redistributed in any way, except for individual class instruction.
Revised August 2011
11. A solution containing tetramminecadmium(II) ions is treated with dilute acid.
[Cd(NH3)4]2+ + 4H+  Cd2+ + 4NH4+
ANSWER: NH3
12. Calcium metal is added to a dilute solution of hydrochloric acid.
Ca + 2H+  Ca2+ + H2
ANSWER: Squeaky pop noise with a lighted splint
13. Equimolar amounts of solutions of sodium dihydrogenphosphate and sodium hydroxide are
mixed.
H2PO4- + OH-  H2O + HPO423-
ANSWER: PO4
14. Solid calcium oxide is exposed to a stream of carbon dioxide gas.
CaO + CO2  CaCO3
ANSWER: Bubbles of CO2 gas as the carbonate reacts with the acid
15. Magnesium turnings are added to a solution of iron (III) chloride.
Mg + 2Fe3+ Mg2+ + 2Fe2+
ANSWER: Mg loses electrons
16. Chlorine gas is bubbled into a solution of sodium bromide.
Cl2 + 2Br-  Br2 + 2ClANSWER: Chlorine gas gains electrons
17. Solid zinc strips are added to a solution of copper (II) sulfate.
Zn + Cu2+  Cu + Zn2+
ANSWER: Zn
18. Solid Lithium oxide is added to water.
Li2O + H2O  2Li+ + 2OHANSWER: Alkali metals
19. Ethene is exposed to a stream of chlorine gas.
C2H4 + Cl2  C2H4Cl2
ANSWER: Addition
20. Solutions of silver nitrate and sodium chromate are mixed.
2Ag+ + CrO42-  Ag2CrO4
ANSWER: Precipitation and double displacement
C:\Users\Adrian\Dropbox\ADCP\apwsheet12aanswers.doc
Page 2 of 2
None are “no reaction”
Write the balanced, net ionic equation, i.e. show significantly ionized species as separate
ions and cancel out spectators
Do NOT include state symbols
Î
Î
C:\Users\Adrian\Dropbox\ADCP\apwsheet12a.doc
What is the change in oxidation state of the Li?
4. Lithium metal is burned in air.
What would be the pH of the resulting solution? Explain.
3. Phosphorous trichloride is added to water.
Which halogen is the best oxidizing agent? Explain.
Î
2. A solution containing iodide ions is added to a solution containing iron(III) ions.
Which substance is oxidized in the reaction?
Î
Page 1 of 4
1. A solution of potassium permanganate is added to a solution of conc. hydrochloric acid.
x
x
x
Write balanced, net ionic equations and answer the questions for the following, noting that;
Î
C:\Users\Adrian\Dropbox\ADCP\apwsheet12a.doc
What might one observe in this reaction?
Î
10. Small chunks of solid sodium are added to water.
What is the electronic structure of the manganese product?
Î
9. Manganese(IV) oxide is added to a solution of hydrobromic acid.
Page 2 of 4
Which homologous series (family) of organic compounds does propane belong to?
8. Propane is burned completely in air.
What are the spectator ions in this reaction?
Î
7. A solution of calcium hydroxide is added to a solution of magnesium chloride.
What color change might one expect to observe?
Î
6. A solution of tin (II) sulfate is added to a solution of iron(III) sulfate.
What color change might one expect to observe?
Î
5. A solution of potassium dichromate is added to an acidified solution of sodium sulfite.
Revised August 2011
Revised August 2011
AP WORKSHEET 12a: Net Ionic Equation Writing I
© Adrian Dingle’s Chemistry Pages 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012. All rights reserved.
These materials may NOT be copied or redistributed in any way, except for individual class instruction.
© Adrian Dingle’s Chemistry Pages 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012. All rights reserved.
These materials may NOT be copied or redistributed in any way, except for individual class instruction.
C:\Users\Adrian\Dropbox\ADCP\apwsheet12a.doc
Which substance is reduced?
Î
16. Chlorine gas is bubbled into a solution of sodium bromide.
Which substance is oxidized in this reaction?
Î
15. Magnesium turnings are added to a solution of iron(III) chloride.
If the product were exposed to an acidic environment, what would be observed?
Î
14. Solid calcium oxide is exposed to a stream of carbon dioxide gas.
Page 3 of 4
If excess hydroxide ions had been added instead, suggest the formula of an ion that may
have been produced?
Î
C:\Users\Adrian\Dropbox\ADCP\apwsheet12a.doc
Categorize this reaction in two ways?
Î
20. Solutions of silver nitrate and sodium chromate are mixed.
Î
19. Ethene is exposed to a stream of chlorine gas.
13. Equimolar amounts of solutions of sodium dihydrogenphosphate and sodium hydroxide are
mixed.
What type of reaction is this?
What is the name of the group of elements that Lithium is a member of?
Describe a simple laboratory test for the gas produced in this reaction?
Î
18. Solid Lithium oxide is added to water.
12. Calcium metal is added to a dilute solution of hydrochloric acid.
Î
Which substance is the reducing agent?
Which substance acts as the base in this reaction?
Page 4 of 4
17. Solid zinc strips are added to a solution of copper(II) sulfate.
11. A solution containing tetramminecadmium(II) ions is treated with dilute acid.
Î
Revised August 2011
Revised August 2011
Î
© Adrian Dingle’s Chemistry Pages 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012. All rights reserved.
These materials may NOT be copied or redistributed in any way, except for individual class instruction.
© Adrian Dingle’s Chemistry Pages 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012. All rights reserved.
These materials may NOT be copied or redistributed in any way, except for individual class instruction.
© Adrian Dingle’s Chemistry Pages 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012. All rights reserved.
These materials may NOT be copied or redistributed in any way, except for individual class instruction.
Revised August 2011
AP WORKSHEET 12c: ANSWERS
1. A solution of sodium hydroxide reacts with a solution of hydrochloric acid.
H+ + OH-  H2O
ANSWER: Sodium and chloride ions
2. A solution of potassium thiocyanate is added to a solution of iron(III) sulfate.
SCN- + Fe3+  [FeSCN]2+
ANSWER: None, Fe
3+
on both sides of the equation
3. Dinitrogen trioxide is added to water.
N2O3 + H2O  2HNO2
ANSWER: Nitrous acid
4. Potassium metal is burned in air.
4K + O2  2K2O
ANSWER: Potassium changes from 0 to +1 by losing electrons
5. A solution of acidified sodium dichromate has a solution of iron (II) ions added to it.
6Fe2+ + Cr2O72- + 14H+  2Cr3+ + 7H2O + 6Fe3+
2+
ANSWER: Fe
3+
 Fe
+e
-
6. Solutions of zinc chloride and potassium phosphate are mixed.
3Zn2+ + 2PO43-  Zn3(PO4)2
ANSWER: A lilac color since potassium ions are in solution
7. Magnesium metal is heated strongly in a stream of nitrogen gas.
3Mg + N2  Mg3N2
ANSWER: -3
8. A solution of acidified potassium permanganate is added to a solution of tin (II) ions.
5Sn2+ + 2MnO4- + 16H+  5Sn4+ + 2Mn2+ + 8H2O
ANSWER: REDOX, electrons are transferred
9. Ethene is reacted with steam.
C2H4 + H2O  C2H5OH
ANSWER: Alcohols
10. Gaseous hydrogen iodide is dissolved in water.
HI + H2O  H3O+ + I+
ANSWER: Water is a base since it accepts H ions
C:\Documents and Settings\AdrianD\My Documents\Dropbox\ADCP\apwsheet12canswers.doc
Page 1 of 2
© Adrian Dingle’s Chemistry Pages 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012. All rights reserved.
These materials may NOT be copied or redistributed in any way, except for individual class instruction.
Revised August 2011
11. Chlorine gas is bubbled into cold, dilute sodium hydroxide solution.
Cl2 + 2OH-  ClO- + Cl- + H2O
ANSWER: Chlorine changes from 0 to +1 AND -1
12. Sulfur trioxide is bubbled into water.
SO3 + H2O  H+ + HSO4ANSWER: It can acts as an acid by donating H
+
13. Sodium metal is heated in a stream of chlorine gas.
2Na + Cl2  2NaCl
ANSWER: REDOX/Composition/Synthesis
14. Solid magnesium carbonate is heated strongly.
MgCO3  MgO + CO2
ANSWER: Decomposition
15. Pieces of magnesium metal are added to a solution of copper (II) sulfate.
Cu2+ + Mg  Mg2+ + Cu
ANSWER: Blue (Cu
2+
ions) changes to a colorless solution of Mg
2+
16. Acidified hydrogen peroxide is added to a solution containing iodide ions.
2I- + 2H+ + H2O2  2H2O + I2
ANSWER: London dispersion forces
17. Dilute nitric acid is added to copper(II) sulfide.
3CuS + 8H+ + 2NO3- 2NO + 4H2O + 3Cu2+ + 3S
ANSWER: 2- to 0
18. Magnesium oxide has sulfur trioxide gas passed over it.
MgO + SO3  MgSO4
ANSWER: One
19. Propyne is exposed to bromine.
C3H4 + 2Br2  C3H4Br4
ANSWER: 6 sigma, 2 pi
20. A solution of barium chloride is added to a solution of potassium sulfate.
Ba2+ + SO42-  BaSO4
ANSWER: A white ppt of BaSO4
C:\Documents and Settings\AdrianD\My Documents\Dropbox\ADCP\apwsheet12canswers.doc
Page 2 of 2
Î
Î
C:\Documents and Settings\AdrianD\My Documents\Dropbox\ADCP\apwsheet12c.doc
Which species is oxidized in the reaction?
4. Potassium metal is burned in air.
What is the name of the product?
3. Dinitrogen trioxide is added to water.
What is the change in oxidation state of the Fe species?
Î
2. A solution of potassium thiocyanate is added to a solution of iron(III) sulfate.
What are the spectator ions in this reaction?
Î
1. A solution of sodium hydroxide reacts with a solution of hydrochloric acid.
Page 1 of 4
None are “no reaction”
Write the balanced, net ionic equation, i.e. show significantly ionized species as separate
ions and cancel out spectators
Do NOT include state symbols
Write balanced, net ionic equations and answer the questions for the following, noting that;
Î
Î
C:\Documents and Settings\AdrianD\My Documents\Dropbox\ADCP\apwsheet12c.doc
What is the role of water in this reaction? Explain
Î
10. Gaseous hydrogen iodide is dissolved in water.
To which homologous series (family) does the organic product belong?
9. Ethene is reacted with steam..
What type of reaction is occurring here? Explain
Î
8. A solution of acidified potassium permanganate is added to a solution of tin(II) ions.
What is the final oxidation state of N?
7. Magnesium metal is heated strongly in a stream of nitrogen gas.
Page 2 of 4
If a flame test were conducted on the result solution, what might one expect to observe?
Î
6. Solutions of zinc chloride and potassium phosphate are mixed.
Write a half equation to show the change in Fe in this reaction?
Î
5. A solution of acidified sodium dichromate has a solution of iron(II) ions added to it.
Revised August 2011
Revised August 2011
AP WORKSHEET 12c: Net Ionic Equation Writing III
© Adrian Dingle’s Chemistry Pages 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012. All rights reserved.
These materials may NOT be copied or redistributed in any way, except for individual class instruction.
© Adrian Dingle’s Chemistry Pages 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012. All rights reserved.
These materials may NOT be copied or redistributed in any way, except for individual class instruction.
C:\Documents and Settings\AdrianD\My Documents\Dropbox\ADCP\apwsheet12c.doc
What type of bonding exists between molecules of iodine?
Î
16. Acidified hydrogen peroxide is added to a solution containing iodide ions.
What color change might one expect to observe?
Î
15. Pieces of magnesium metal are added to a solution of copper(II) sulfate.
What type of reaction is this?
Î
C:\Documents and Settings\AdrianD\My Documents\Dropbox\ADCP\apwsheet12c.doc
What color change might be observed?
20. A solution of barium chloride is added to a solution of potassium sulfate.
14. Solid magnesium carbonate is heated strongly.
Î
How many sigma and pi bonds in Propyne?
What type of reaction is this?
Î
19. Propyne is exposed to bromine.
13. Sodium metal is heated in a stream of chlorine gas.
Î
The Lewis diagram for sulfite has how many lone pairs around the central atom?
Explain the role of the product in this reaction?
Î
18. Magnesium oxide has sulfur trioxide gas passed over it.
12. Sulfur trioxide is bubbled into water.
Î
What is the change in oxidation state of sulfur in this reaction?
This reaction is classified as a disproportionation, why?
Page 3 of 4
Page 4 of 4
17. Dilute nitric acid is added to copper(II) sulfide.
11. Chlorine gas is bubbled into cold, dilute sodium hydroxide solution.
Î
Revised August 2011
Revised August 2011
Î
© Adrian Dingle’s Chemistry Pages 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012. All rights reserved.
These materials may NOT be copied or redistributed in any way, except for individual class instruction.
© Adrian Dingle’s Chemistry Pages 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012. All rights reserved.
These materials may NOT be copied or redistributed in any way, except for individual class instruction.
Chemistry
Mr. Bennett
Name_____________
NH3(aq) +
HClO3(aq)
NH4+(aq) +
ClO3–(aq)
HCN(aq) +
CO32–(aq)
HCO3–(aq) +
CN–(aq)
NH3(aq) +
HF(aq)
F- (aq) +
NH4+(aq)
CO32–(aq) +
HClO3(aq)
HCO3–(aq) +
ClO3–
HOCl (aq) +
NH3 (aq)
OCl- (aq) +
NH4+ (aq)
HF (aq) +
CO32– (aq)
F–(aq) +
HCO3–(aq)
NH3(aq) +
HNO2(aq)
NH4+(aq) +
NO2–(aq)
CO32–(aq) +
HOCl(aq)
HCO3–(aq) +
OCl–(aq)
NH3(aq) +
HC2H3O2(aq)
NH4+(aq) +
C2H3O2–
CO32–(aq) +
HNO2(aq)
HCO3–(aq) +
NO2–(aq)
HClO3(aq) +
NH2(aq)
NH4+(aq) +
ClO2–(aq)
CO32–(aq) +
HC2H3O2(aq)
HCO3–(aq) +
C2H3O2–(aq)
NH3(aq) +
HBrO3(aq)
NH4+(aq) +
BrO3–(aq)
CO32–(aq) +
HClO3(aq)
HCO3–(aq) +
ClO3–(aq)
NH3(aq) +
HIO3(aq)
NH4+(aq) +
IO3–(aq)
CO32–(aq) +
HBrO3(aq)
HCO3–(aq) +
BrO3–(aq)
Advanced Chemistry
Mr. Bennett
Name_________________
Date________
Predict the oxidation number of the underlined element.
NaIO3
MnO
LiH
CoSO4
Sr(NO3)2
RaCl2
Hg(NO3)2
CaC2O4
NaNO3
Al(ClO3)3
HgF2
K2SO4
CoS
SrI2
Fe(NO3)3
MgSiO3
NH4F
Pb(CN)2
AgBr
Ag2S
MgH2
Ca3(PO4)2
H2SO4
Determine if the following reactions are redox reactions. If yes, then label the element that is
oxidized, the element that is reduced, the oxidizing agent and the reducing agent.
1. (NH4)2Cr2O7  Cr2O3 + N2 + H2O
1. Ag2S + KCN  KAg(CN)2 + K2S
2. NaHCO3 ---> Na2CO3 + CO2 + H2O
3. Au2S3 + H2 ---> Au + H2S
4. Fe2(C2O4)3 ---> FeC2O4 + CO2
5. ClO2 + H2O ---> HClO2 + HClO3
6. Ca3P2 + H2O ---> Ca(OH)2 + PH3
7. K2O
+ CO2 ---> K2CO3
8. As + NaOH ---> Na3AsO3 + H2
9. MgNH4PO4 ---> Mg2P2O7 + NH3 + H2O
10. MnO2 + HCl ---> MnCl2 + H2O + O2
11. Pb+6 + Na + C2H5Cl ---> Pb(C2H5)4 + NaCl
12. Ca(OH)2 + H3PO4 ---> CaHPO4 + H2O
13. Zn + NaOH + H2O ---> Na2Zn(OH)4 + H2
14. SrBr2 + (NH4)2CO3 ---> SrCO3 + NH4Br
15. Hg(OH)2 + H3PO4 ---> Hg3(PO4)2 + H2O
16. Ca3(PO4)2 + SiO2 + C ---> CaSiO3 + P4 + CO
17. I4O9 ---> I2O6 + I2 + O2
18. C2H3Cl + O2 ---> CO2 + H2O + HCl
19. (NH4)2Cr2O7 ---> NH3 + H2O + Cr2O3 + O2
Common Oxidizing and Reducing Agents You Should Memorize
Oxidizing
Agent
Turns In To…
Reducing
Agent
Turns In To…
MnO4(in acid)
MnO4(in neutral or basic)
MnO2
(in acid)
Cr2O72(in acid)
HNO3
(conc.)
HNO3
(dilute)
H2SO4
(hot and conc.)
Highly charged
metal cations
Free Halogens
(Cl2, Br2, I2, F2)
H2O2
(in acid)
Mn2+
Free Halogens
(Cl2, Br2, I2, F2)
Metal cations
Mn2+
Halide ions
(Cl-, Br-, I-, F-)
Free metals
(eg. Zn)
SO32- or SO2
Cr3+
NO2-
NO3-
NO2
Free halogens
(in dilute basic)
Free halogens
(in conc. Basic)
Lower charged
metal cations
H2O2
(in basic)
S2O32-
Hypohalite ions
(XO-) + halide (X-)
Halite ions (XO3-)
H2
H+ usually in the
form of water
MnO2
NO
SO2
Lower charged
metal cations
Halide ions
(Cl-, Br-, I-, F-)
H2O
SO42-
Highly charged
metal cations
O2 + H2O
S4O62-
Examples:
Sulfur dioxide gas is bubbled through a solution of acidified potassium manganate (VII)
(permanganate)
-
SO2 + MnO4
+ H
+
2-
H2O + SO4
2+
+ Mn
Hydrogen peroxide is added to an acidified solution of potassium dichromate (VI)
+
H2O2 + H
2-
+ Cr2O7
Cr
3+
O2 + H2O
Concentrated hydrochloric acid is added to solid manganese (IV) oxide
H
+
+ Cl
-
+ MnO2
2+
Mn
Cl2 + H2O
Predicting Redox Reaction Products:
Common Oxidizing Agents
MnO41- in acidic solution
MnO2 in acidic solution
MnO41- in neutral or basic solution
Cr2O72- in acidic solution
HNO3, concentrated
HNO3, dilute
H2SO4, hot, concentrated
Metallic ions (higher oxidation #)
Free halogens
Na2O2
HClO4
C2O42H2O2
Common Reducing Agents
Halide ions
Free metals
Sulfite ions or SO2
Nitrite ions
Free halogens, dilute basic solution
Free halogens, conc. basic sol.
Metallous ions (lower oxidation #)
Products Formed
Mn2+
Mn2+
MnO2(s)
Cr3+
NO2
NO
SO2
Metallous ions (lower oxidation #)
Halide ions
NaOH
Cl1CO2
O2
Products Formed
Free halogen
Metal ions
Sulfate ions
Nitrate ions
Hypohalite ions
Halate ions
Metallic ions (higher oxidation #)
omplex Ion Formation
These are usually formed from a transition metal surrounded by ligands (polar molecules or negative
ions). As a "rule of thumb" you place twice the number of ligands around an ion as the charge on the
ion... example: the dark blue Cu(NH3)42+ (ammonia is used as a test for Cu2+ ions), and Ag(NH3)2+.
Memorize the common ligands.
Ligands
Names used in the ion
H 2O
aqua
NH3
ammine
OH-
hydoxy
-
chloro
Br-
bromo
CN-
cyano
Cl
thiocyanato (bonded through sulphur)
-
SCN
isothiocyanato (bonded through nitrogen)
Watchout for:
Alumninum also forms complex ions as do some post transitions metals. Ex: Al(H 2O)63+
The names are very impressive, but easy..the ions above are the tetraamminecopper(II) ion, the
diamminesilver(I) ion, and hexaaquoaluminum(III) ion. Zn(OH)42- is the tetrahydroxyzinc(II) ion,
the charge is the sum of the parts (2+)+4(-1)= -2.
Acid-base reactions may change NH3 into NH4+ (or vice versa) which will alter its ability to act as a
ligand.
Visually, a precipitate may go back into solution as a complex ion is formed. For example, Cu 2+ + a
little NH4OH will form the light blue precipitate, Cu(OH)2. With access ammonia, the complex,
Cu(NH3)42+, forms.
Keywords such as "excess" and "concentrated" of any solution may indicate complex ions. AgNO3 +
HCl forms the white precipitate, AgCl. With excess, concentrated HCl, the complex ion, AgCl 2-,
forms and the solution clears.
The odd complex ion, FeSCN2+, shows up once in a while simply because it is commonly used in the
CHEMStudy first-year equilibrium lab.
Transitional metals, such as Iron, Zinc and Chromium, can form complex ions. Aluminum can form
complex ions as well.
AP WORKSHEET 03j: Types of Reaction
Electrolytes & Non-electrolytes
Indicate if you would expect the following compounds to be electrolytes or non-electrolytes when in aqueous
solution (dissolved in water). In each case very briefly explain your answer. Use equations if appropriate. (6)
(a) Sodium fluoride
(b) Methanol (CH3OH, an alcohol similar to ethanol – NOT a hydroxide)
(c) Strontium nitrate
2. Ionic concentrations
Calculate the concentration of the ion indicated in each of the following solutions. The use of square brackets [ ]
denotes concentration in mol L-1. (3)
(a) [K+] in 0.238 M KNO3
(b) [Al3+] and [SO42-] in 0.080 M Al2(SO4)3
3. Precipitation reactions and net ionic equations
Predict if a precipitation reaction will occur in each of the following cases. If it does, write the full, balanced
equation AND the net ionic equation (including state symbols) to show the formation of the precipitate. If there
is no reaction, say so, and indicate why. (9)
(a) CuSO4(aq) + Na2CO3(aq) 
(b) HI(aq) + Zn(NO3)2(aq) 
(c) AgNO3(aq) + NaBr(aq) 
4. Acids and bases & neutralization
(a) Write a full, balanced equation for the reaction of aqueous sulfuric acid and aqueous cesium hydroxide to
produce an aqueous salt and water assuming that sulfuric acid donates BOTH of its hydrogen ions.
Include state symbols. (2)
(b) Rewrite the equation in (a) showing all ions present with state symbols. (2)
(c) Rewrite the equation in (b) removing any spectator ions (i.e. write the net ionic equation) with state
symbols. (2)
5. Oxidation numbers
What is the oxidation number of each of the underlined atoms in each of the following species? Think carefully
about the rules that are being applied and write a very brief, simple explanation of your answer in each case.
(8)
(a) CaI2
(b) GeO2
(c) KO2
(d) NH3
6.
REDOX and half equations
For each of the following ionic solids, write a balanced overall equation to show their formation from their
elements. Then write the two balanced half equations (one showing oxidation, one showing reduction) that show
the formation of the individual ions involved. (9)
(a) Magnesium sulfide
OVERALL:
OXIDATION:
REDUCTION:
(b) Sodium bromide
OVERALL:
OXIDATION:
REDUCTION:
(c) Aluminum chloride
OVERALL:
OXIDATION:
REDUCTION:
7. Disproportionation
(a) Consider the following reaction.
3Cl2  5Cl- + Cl5+
Write two balanced half equations (one oxidation, one reduction) to show the changes that the chlorine species
undergoes. (4)
OXIDATION:
REDUCTION:
(b) Is this reaction a disproportionation? Justify your answer. (2)
8. REDOX Titration calculations
(a) Consider the following half equations.
SO32- + H2O  SO42- + 2H+ + 2e-
MnO4- + 8H+ + 5e-  Mn2+ + 4H2O
Combine these two equations to obtain the overall reaction of sulfite ions with manganate (VII) ions. (2)
(b) Use the equation you have written in (a) to calculate the volume of 0.277 M manganate (VII) ions that are
required to react completely with 20.0 mL of 0.451 M sulfite ions. (4)
9. Classification of chemical reactions
By choosing two of the following reaction types from the list below, classify each of the following reactions in two
ways. (12)
Reaction types: precipitation, acid-base, REDOX (oxidation and reduction), single displacement, double
displacement, combination, decomposition, combustion.
(a) 2NaOH(aq) + CuSO4(aq)  Na2SO4(aq) + Cu(OH)2(s)
AND
(b) HI(aq) + KOH(aq)  KI(aq) + H2O(l)
AND
(c) C3H8(g) + 5O2(g)  3CO2(g) + 4H2O(l)
AND
(d) 2HgO(s)  2Hg(l) + O2(g)
AND
(e) 4B(s) + 3O2(g)  2B2O3(s)
AND
(f) 2Al(s) + 6HNO3(aq)  2Al(NO3)3(aq) + 3H2(g)
AND
Question 1
3.47 g of the hydrated “double salt”, ammonium iron(II) sulfate hexahydrate,
FeSO4(NH4)2SO4.6H2O was dissolved in 200. mL of water. 20.0 mL of the solution had some acid
added to it and then it reacted completely with 12.6 mL of KMnO 4 solution. Calculate the
concentration of the KMnO4 solution given the full REDOX equation below.
5Fe2+ + MnO4- + 8H+  5Fe3+ + Mn2+ + 4H2O
Question 2
When 25.0 mL of a solution of 0.200 M NaIO3 was added to acidified iodide ions, the iodine
produced reacted with 20.3 mL of sodium thiosulfate (Na2S2O3). Calculate the concentration of
sodium thiosulfate solution given the REDOX equations below.
IO3- + 5I- + 6H+  3I2 + 3H2O
I2 + 2S2O32-  2I- + S4O62-
Question 3
3.364 g of hydrated barium chloride BaCl2.xH2O was dissolved in water and made up to a total
volume of 250.0 mL. 10.00 mL of this solution required 46.92 mL of 2.530 x 10 -2 M silver nitrate for
complete reaction. Calculate the value of x in the formula of hydrated barium chloride, given the
net ionic equation for precipitation below.
Cl-(aq) + Ag+(aq) AgCl(s)
Question 4
Calculate the concentration of 45.0 mL of a phosphoric acid solution that neutralized 20.8 mL of
0.532 M sodium hydroxide. Assume complete ionization of the acid.
Question 5
If 0.664 g of an acid was required to neutralize 10.0 mL of 0.800 M NaOH, calculate the Molar
Mass of the acid given it reacts with sodium hydroxide in a 1:2 ratio i.e., 1 ACID : 2 NaOH.
Answers:
1. 0.0140 M
2. 1.48 M
3. 1
4. 0.0820 M
5. 166 g mol-1
Advanced Chemistry
Mr. Bennett
Name___________________
How many grams of Ba(OH)2 are contained in a 25.00 ml solution if 16.52 ml
of 0.850 M HCl are required to completely neutralize the sample?
25.0 ml of 0.625 M HBr are mixed with 42.0 ml of 0.352 M NaOH. Find the
final concentrations of all the ions present in the solution after the reaction
occurs. Will the final solution be acidic, basic, or neutral? Explain.
How many milliliters of 0.114 M H2SO4 solution provide the sulfuric acid
required to react with the sodium hydroxide in 32.2 mL of 0.122 M NaOH
according to the following equation?
What volume of 0.337 M KOH provides enough solute to combine with the
sulfuric acid in 18.6 mL of 0.156 M H2SO4?
5.1 Calculate the molarity of a solution containing,
a) 23.9 g of NaCl dissolved in enough water to have 300 mL of solution
b) 1.69 x 10-3 moles HCl in 12.0 mL of water
5.2 Describe how to prepare the following solutions.
a) 450 mL of 0.500 M NaOH, from solid NaOH
b) b) 900 mL of 1.00 M HCl, from 12.0 M HCl (concentrated HCl)
5.3 In the reaction, Mg + 2 HCl MgCl2 + H2
How many grams of magnesium will react with 250. mL of 0.500 M HCl?
5.4 How many grams of H2 will be produced when 1.00 g of Mg is added to a
250. mL sample of 0.500 M HCl? (Use the chemical reaction in 5.3.)
5.5 Calculate the volume of 0.360 M NaOH needed to neutralize 27.0 mL of
0.820M HCl. (Note: Write the chemical equation.)
5.6 Calculate the concentration of phosphoric acid produced when 2.00 g of
P2O5 is added to 500 mL of distilled water. (Assume the final volume of the
solution is 500 mL.) The important reaction is,
How many moles of water remain unreacted?
5.7 Potassium dichromate in acidic solution is frequently used to determine
the concentration of Fe(II) in solution. The equation which describes the
reaction is:
A solution of Cr2O72- is prepared by dissolving 6.425 g of K2Cr2O in 800.0
mL of water. (Assume no significant change in volume when the solution is
prepared.) A total of 21.35 mL of this solution is required to reach the endpoint in a titration of a 250.0 mL sample containing Fe(II). Determine the
concentration of Fe(II) in the solution.
Originality is the one thing
which unoriginal minds cannot
feel the use of.--John Stuart Mill
Unit 3 Practice Problems (with answers at end)
It is in knowledge as in swimming:
he who flounders and splashes on the
surface makes more noise, and attracts
more attention, than the pearl-diver
who quietly dives in quest of treasures
to the bottom.--Washington Irving
Stoichiometry
1. Sodium reacts with water to form sodium hydroxide and hydrogen gas. How many
grams of H2 can be produced from 11.5 g of sodium?
Limiting reagents in stoichiometry
8. Aluminum and sulfuric acid react in a displacement reaction. If 5.0 g of Al and 45 g
of sulfuric acid are used, what mass of hydrogen is collected? What is the limiting
reagent?
9. A student prepares hydrogen bromide gas by reacting sodium bromide with
phosphoric acid. Sodium phosphate is a by-product. If 24.3 g of sodium bromide is
used with 100.0 g of phosphoric acid, how many grams of hydrogen bromide gas can
be collected? What is the limiting reagent?
2. Hydrochloric acid reacts with calcium hydroxide to produce water and calcium
chloride. How many grams of HCl are required to react with 10.0 g of calcium
hydroxide?
3. Nitrogen reacts with hydrogen to make ammonia. How many grams of ammonia can
be produced from 2.00 g of hydrogen?
4. Potassium chlorate decomposes when heated to give oxygen gas and potassium
chloride. How many grams of oxygen gas can be obtained in this way starting with
1.226 g of KClO3?
5. Phosphorus trichloride is made when white phosphorus (P4) reacts with chlorine
gas. How many grams of phosphorus are required to produce 5.49 g of phosphorus
trichloride?
6. Ethene gas (C2H4) burns in oxygen to form carbon dioxide and water. How many
grams of ethene must be burned to produce 200 g (to the nearest gram) of carbon
dioxide?
7. Magnesium metal reacts with sulfuric acid in a displacement reaction. How
many grams of hydrogen gas will be produced when 4.05 g of magnesium reacts
completely?
It's what we learn after
we think we know it all
that counts.--Kin Hubbard
Molarity
10. Calculate the Molarity of a solution which contains 49.0 g of phosphoric acid in
2000.0 mL of solution.
11. Calculate the mass of solute in 1.5 L of solution which is 0.240 M in potassium
dihydrogen phosphate.
12. How many grams of lead(II) acetate must be used to make 500.0 mL of a solution
that is to contain 10 mg/mL of lead(II) acetate? What is the Molarity of the solution?
13. What volume (in Litres) of 0.100 M sodium chloride solution can be prepared from
117 g of the salt?
14. A test solution of aluminum nitrate must be made that is 20.0 g/L in the salt. If
1500.0 mL of the solution is desired, how many grams of the solute must be used?
What is the Molarity of the solution? What is the Molarity of nitrate ion in the
solution?
Gravimetric analysis
15. What mass of AgBr is produced when100.0 mL of 0.150 M AgNO3 is added to 20.0
mL of 1.00 M NaBr?
20. A 50.00 mL sample of solution containing Fe2+ ions is titrated with a 0.0216 M
KMnO4 solution. It required 20.62 mL of the KMnO4 solution to oxidize all of the Fe2+
to Fe3+ ions by the reaction:
MnO4- + Fe2+ → Mn2+ + Fe3+
(unbalanced)
16. Aluminum can be determined gravimetrically by reaction with a solution of 8hydroxyquinoline (C9H7NO). The net ionic equation is:
Al + 3 C9H7NO →Al(C9H6NO)3 + 3 H
3+
What was the concentration of the Fe2+ solution?
+
A mass of 0.1248 g of Al(C9H6NO)3 was obtained by precipitating all of the Al3+ from a
solution prepared by dissolving 1.8571 g of a mineral. What is the mass percent of
aluminum in the mineral sample?
Next to being a great poet
is the power of understanding
one.--Longfellow
Acid/Base titration
17. In standardizing an NaOH solution, a student found that 38.46 cm3 of the base
neutralized exactly 32.33 cm3 of 0.1064 M HCl. Find the concentration (M) of the
NaOH.
18. In titrating an H2SO4 solution, it was found that 23.66 cm3 of 0.2137 M NaOH
would neutralize 22.04 cm3 of the acid. Find the concentration of the H2SO4.
Redox titration
19. A solution of permanganate is standardized by titration with oxalic acid
(H2C2O4). It required 28.97 mL of the permanganate solution to react completely
with 0.1058 g of oxalic acid. The unbalanced reaction is:
MnO4- + H2C2O4 → Mn2+ + CO2
(unbalanced)
What is the Molarity of the permanganate solution?
(H+)
Answers:
1. 0.50 g
2. 9.86 g
3. 11 g
4. 0.480 g
5. 1.24 g
6. 63.8 g
7. 0.33 g
8. 0.58 g, Al
9. 19.1 g, NaBr
10. 0.250 M
11. 49 g
12. 5.0 g, 0.031 M
13. 20.0 L
14. 30.0 g, 0.0940 M, 0.282 M
15. 2.82 g
16. 0.3947%
17. 0.08944 M
18. 0.1147 M
19. 1.622 x 10-2 M
20. 4.45 x 10-2 M
(H+)
Advanced Chemistry
Mr. Bennett
Name______________
October 16, 2007
1. The iron content of iron ore can be determined by titration with
standardized KMnO4 solution. The iron ore is dissolved in HCl, and all
the iron is reduced to Fe+2 ions. The solution is then titrated with
KMnO4 solution, producing Fe+3 and Mn+2 ions in acidic solution
according the equation below. If it requires 41.95 ml of 0.0205 M
KMnO4 to titrate a solution made from 0.6128 g of iron ore, what is
the percentage of iron in the ore?
MnO4-(aq) + 5 Fe+2(aq) + 8 H+(aq)  5 Fe+3(aq) + Mn+2(aq) + 4 H2O(l)
2. A 16.75 ml, 1.67 M CaCl2 solution is mixed with 38.62 ml of 0.759 M
CaCl2 solution. Calculate the molarity of the Cl- ions in the final
solution.
Part I: Reactions
Review your quiz
Part II: Solve the following calculations; include your work, correct significant digits, and
units with your answers.
1. A solution is made by dissolving 15.9 grams of HCl in 125.0 ml of 1.25 M LiOH.
a. Is the final solution acidic, basic, or neutral?
b. Calculate the molarity of all of the ions present after the reaction takes place.
2. What volume, in ml, of 0.475M LiCl is needed to precipitate all of the Pb+2 ions from
140.0 ml of a 0.325 M Pb(NO3)2 solution?
3. A solution is prepared by dissolving 47.5 grams of (NH4)2SO4 in enough water to make
750.0 ml of solution. A 75.5 ml sample of this solution is then diluted to 425.0 ml. What is
the molarity of the NH4+ and SO4-2 ions in this final solution?
4. A sample containing only Lead (II) nitrate and Lead (II) acetate is dissolved and treated
with NaCl. A 3.500 gram sample of the salt mixture produced 1.005 grams of PbCl2 as a
precipitate. Calculate the percentage of Lead (II) in the original sample.