CHM 1032C Tentative Grading Outline Fall 2015

 

Chapter 5 Classification & Balancing Chemical Reactions

E._____ (02) Writing Reactions/ Symbols-Page 7 & Section 5.1 Answers

E1.____ (02) Classifying Chemical Reactions- Lecture & Section 5.3 Answers

F._____ (04) Balancing Chemical Equations -Sections 5.2 Answers ef

G._____(02) Predicting Single Replacement Products Lecture Answers

H._____( 02) Predict Double Replacement Sections 5.4 Answers h

H1____ (02) Neutralization/Gas Forming Reactions Section 5.5 & Lecture Answers

W. _____(06) Rewrite Equations Ionically Section 5.8 Answers

R. _____(06) Redox Equations-Sections-Section 5.6-5.7 Answers

______(26) Total = ______%

 

McMurry GOB Chapter 5 Table Contents

5. Classification and Balancing of Chemical Reactions
5.1 Chemical Equations M-5E
5.2 Balancing Chemical Equations M-5F
5.3 Classes of Chemical Reactions M-5E1
5.4 Precipitation Reactions and Solubility Guidelines M-5H
5.5 Acids, Bases, and Neutralization Reactions M-5H1
5.6 Redox Reactions M-8H
5.7 Recognizing Redox Reactions
5.8 Net Ionic Equations M-8G

 

From Your Hein Textbook and Power Point for Chapter 8, what is a chemical equation?

 

 

 

Evidence for Chemical Reactions

 

There are four observations that indicate a chemical reaction is taking place:

 

1.      A gas is produced.

Gas may be observed in many ways in a reaction from light fizzing to heavy bubbling.

 

2.      An insoluble solid is produced in a solution.

a.    A substance dissolves in water to give an aqueous solution.

b.    If we add two aqueous solutions together, we may observe the production of a solid substance.

c.    The insoluble solid formed is called a precipitate

 

3.      A permanent color change is observed.

a.    Many chemical reactions involve a permanent color change.

b.    A change in color indicates that a new substance has been formed

 

4.      An energy change is observed

a.    A reaction that releases heat is an exothermic reaction.

b.    A reaction that absorbs heat is an endothermic reaction.

c.    Examples of a heat energy change in a chemical reaction are heat and light being given off.

From the Corwin Textbook, the Chemical symbols are explained:

fg08_T01

 

 

 

 

 

 

Chapter 5 Homework Packet

 

Chapter 5-Part E Basic Stoichiometry Definitions 2 points

 

Fill in the following with the symbols used in chemical equations which has the stated translation or meaning(s) (Section 7.2 Table 7.1 page 191 Corwin 7th ) (Hein Section 8,1 page 144)::

 

_________1. Produces, yields, gives

 

 

_________2. Reacts with, added to, plus

 

 

_________ and _________ 3. Solid substance or precipitate forms

 

 

_________and _________4. Gaseous substance formed

 

 

_________5. Liquid Substance

 

 

________5a. Water or aqueous solution

 

 

_________6. Reversible Reaction

 

 

_________7. No Reaction

 

 

 

8. Show the symbol for heat:__________

 

 

9. How would you show a catalyst in a chemical reaction where A plus B forms products D and E, but is catalyzed by substance C

 

 

A + B D + E

 

10. Define Catalyst (See Section 7.6 page 193)

 

 

 

Chapter 5 Homework Packet

Although McMurry does not define the following five types of reactions: Combination, Decomposition, Single Replacement, Double Replacement, and Neutralization reactions are introduced. The table 8.3 from another text is a summary.

fg08_T03

From another book:

From lecture, I will tell you a chemical change via a chemical reaction is either a NON-REDOX or a REDOX change. Combination, Decomposition, Single Replacement and Oxidation-Reduction (more complicated) are REDOX changes. Only Double Replacement, Double Displacement or sometimes called Metatarsus reactions are NON-REDOX and I like to call them Ion-Exchange Reactions,.

Our text discusses precipitation reactions in section 5.4 , but leave off:

Gas Forming Reactions.

 

When predicting the products of a double replacement reaction, sometimes one of the products instantly decomposes.

 

 

If H2CO3 is a predicted product in ion exchange, it is written as

CO2 and H2O.

 

For example:

Na2CO3 (aq) + HCl (aq) [H2CO3](aq) + NaCl (aq)

 

Should be written:

Na2CO3 (aq) + HCl (aq) CO2(g) + H2O (l) + NaCl (aq)

 

Two other products which are shown differently:

[NH4OH] NH3 + H2O

 

[H2SO3 ] SO2 + H2O

 

 

In Section 12.8, there is a another type of chemical reaction:

 

Combustion a substance burns in the presence of oxygen. Combustion of a compound that contains C and H (or C, H, and O) produces carbon dioxide gas and water.

CH2O(l) + O2(g) → CO2(g) + H2O(l)

 

The general type of combustion problem looks like this:

 

CxHy [(l) or (g)] + O2 (g) CO2 (g) + H2O (g)

Or

 

CxHyOz[(s) or (l) or (g)] + O2 (g) CO2 (g) + H2O (g)

 

 

The chemical reaction for the combustion of gasoline:

C8H18 (l) + O2 (g) CO2 (g) + H2O (g)

Octane oxygen gas carbon dioxide water

 

 

 

reactions

 

Module 5 E1: Classification of Chemical Reactions 2 Points

(Sections 7.4)

Classify Each of the following (unbalanced) chemical reactions as:

  1. Combination (or synthesis)
  2. Decomposition (or Anaylsis)
  3. Single Replacement
  4. Double Replacement (Precipitation)
  5. Double Replacement (Neutralization)
  6. Double Replacement (Gas Forming)
  7. Combustion of a hydrocarbon

 

______1. Fe + FeCl3 FeCl2

 

____2. HCl + Mg(OH)2 MgCl2 + HOH

 

_____3. Mg + HNO3 Mg(NO3)2 + H2

 

_____4. H2 + N2 NH3

 

____5. NaHCO3 + HCl NaCl + CO2 + H2O

 

____6. Ca(NO3)2 + K3PO4 Ca3(PO4)2 + KNO3

 

____7. KClO3 KCl + O2

 

____8. Na + H2O NaOH + H2

 

 

 

Writing Chemical Reactions (Section 5.1-5.6)

 

9. Write a chemical equation for solid cadmium hydrogen carbonate decomposing to yield solid cadmium carbonate, water, and carbon dioxide gas:

 

 

 

10. Write a chemical equation for the reaction of aqueous solutions of potassium chromate and calcium sulfate to give the precipitate calcium chromate and aqueous potassium sulfate.

 

 

 

 

Writing Chemical Reactions

 

11. Write a chemical equation or solid sodium hydrogen carbonate decomposing to yield solid cadmium carbonate, water, and carbon dioxide gas:

 

 

 

12. Write a chemical equation for the reaction of aqueous solutions of potassium chromate and lead(II) nitrate to give the precipitate lead(II) chromate and aqueous potassium nitrate.

 

 

 

 

 

 

 

Rules and Suggestions for Balancing Equations

1)    The same # and type of atom must be present on each side of the equation.

2)    Balancing is accomplished by adding coefficients. NEVER change the subscripts.

3)    Coefficients must be in the smallest whole # ratio.

4)    Balancing is done by trial and error.

5)    Usually Balance Hs and Os last or an element that appears in more than one place of either side of the reaction .

6)      Balance polyatomic ions as one unit in Ion Exchange reactions.

 

 

Chapter 5 Homework Packet

 

Example of balancing an Equation:

 

Chapter 5-Part F Balancing Chemical Equations 4 points

Balance the following chemical equations (write the chemical formulas in #10 then balance):

 

1. Fe + FeCl3 FeCl2

 

 

2. Al + O2 Al2O3

 

 

3. Na2CO3 + C + N2 NaCN + CO

 

 

4. FeS + O2 Fe2O3 + SO2

 

 

5. IBr + NH3 NI3 + NH4Br

 

 

 

6. Cl2 + HOH HCl + HClO

 

 

 

7. AgNO3 AgNO2 + O2

 

 

 

8. HClO4 + P4O10 H3PO4 + Cl2O7

 

 

 

9. HCl + Mg(OH)2 MgCl2 + HOH

 

 

 

10. Sodium hydroxide + Hydrochloric acid sodium chloride + water

 

 

 

You may check your work using the online chemical equation balancer at:

http://people.emich.edu/bramsay1/ccc-release/chem.html

Video:
https://www.khanacademy.org/test-prep/mcat/physical-processes/stoichiometry/v/balancing-chemical-equations


Chapter 5 Homework Packet

 

Chapter 5 Homework Packet

 

 

 

 

 

 

 

Chapter 5 Homework Packet

 

 

 

 

 

Chapter 5 Homework Packet

 

If you were to (H2O) in the activity series like an acid is shown as (H), where would you put it? Show below:

 

Given the following Activity Series:

 

Li > K > Ba > Sr > Ca > Na > Mg > Al >

Mn > Zn > Fe > Cd > Co > Ni > Sn >

 

Pb > (H) > Cu > Ag > Hg > Au

 

The rule to follow is a single replacement reaction takes place only if the metal or (H) is more active than the metal or (H) it is replacing. Li will react with everything, while Hg will replace only gold. And poor gold does not react with any of the cations of metals. Therefore gold is found pure in nature, while the very active metals such as potassium and sodium are never found pure in nature, but are found as minerals (ionic compounds).

Will Mg metal react with Nitric Acid? Yes
(Mg has a great reactivity then [H] in the series)

Mg (s) + 2 HNO3 (aq)   →  Mg(NO3)2 (aq)  + H2 (g)

Will Copper react with Nitric Acid? no
(Cu is below [H] in the activity series)

Cu (s)  +  HNO3 (aq)  →  no reaction

Given the following Active Metals:

Li > K > Ba > Sr > Ca > Na> (H2O)

The six very active metals are so reactive they will replace one of the two hydrogens in water and form alkaline hydroxides as products.  Hydrogen gas will bubble out of the solution. See some of the above movies for demonstrations.

Will Sodium react with water?  yes
(Na is one of the six active metals above)

2 Na(s) + 2 HOH (l)  2 NaOH (aq)  +  H2 (g)

Chapter 5 Homework Packet

Part G Single Replacement Reactions 2 points

 

Given the following Activity Series:

Li > K > Ba > Sr > Ca > Na > Mg > Al > Mn > Zn > Fe > Cd > Co > Ni >

Sn > Pb > (H) > Cu > Ag > Hg > Au

 

Given the following Active Metals:

Li > K > Ba > Sr > Ca > Na

 

Complete the products of the following reactions, then balance the equation (If no reaction write NR):

 

1. Cu (s) + Al(NO3)3 (aq)

 

 

 

 

2. Al (s) + Cu(NO3)2 (aq)

 

 

 

 

 

3. Au (s) + H2SO4 (aq)

 

 

 

 

 

4. Ca (s) + H2O (l)

 

 

 

 

 

 

5. Mn (s) + H2O (l)

 

 

 

 

Chapter 5 Homework Packet

IonExchangeGraphic

Except in neutralization and gas forming reactions.

 

 

Chapter 5 Part H Double Replacement Reactions 2 points

Given the following Solubility Rules for Ionic Compounds:

Compounds containing the following ions are generally soluble in water:

1. Alkali metal ions and ammonium ions, Li+ , Na+ , K+ , NH4+

2. Acetate ion, C2H3O2-

3. Nitrate ion, NO3-

4. Halide ions (X), Cl- , Br- , I- (AgX, Hg2X2 , and PbX2 are insoluble exceptions)

5. Sulfate ion, SO4 2- (SrSO4, BaSO4 , and PbSO4 are insoluble exceptions)

 

Compounds containing the following ions are generally insoluble in water:

6. Carbonate ion,CO32- (see rule 1 exceptions which are soluble)

7. Chromate ion CrO42- (see rule 1 exceptions which are soluble)

8. Phosphate ion PO43- (see rule 1 exceptions which are soluble)

9. Sulfide ion, S2- (CaS, SrS, BaS, and rule 1 exceptions are soluble in water)

10. Hydroxide ion, OH- [ Ca(OH)2 , Sr(OH)2 , Ba(OH)2 , and rule 1 exceptions are soluble)

 

Complete and balance the following reactions using the above solubility table (write no reaction or NR if both products are soluble or a covalent compounds is not formed)

1. AlCl3 (aq) + K2CO3 (aq)

 

 

2. NiSO4 (aq) + Li3PO4 (aq)

 

 

3. NaCl (aq) + AgNO3 (aq)

 

 

4. H2SO4 (aq) + NaOH (aq)

 

 

5. H3PO4 (aq) + Ba(OH)2 (aq)

 

Video:
http://www.brightstorm.com/science/chemistry/chemical-reactions/double-replacement-reactions/

http://www.youtube.com/watch?v=7hVKb4ROjZw

 

http://www.youtube.com/watch?v=_oixjNeKtxs

 

http://www.youtube.com/watch?v=IMfNi_C2DTg

 

http://www.youtube.com/watch?v=2tIutF6-wn4

 

 

 

 

 

Chapter 5 Homework Packet

Chapter 5 Part H1 Double Replacement Reaction:

Neutralization/Gas Forming Reactions 2 points

 

Complete and balance the following precipitation reactions using the above solubility table

(write no reaction if both products are soluble or a covalent compounds is not formed)

 

1. Mg(OH)2 (s) + H2SO4 (aq)

 

 

 

2. H3PO4 (aq) + KOH (aq)

 

 

 

3. NH4NO3 (aq) + Ba(OH)2 (aq)

 

 

 

4. HBr (aq) + Pb(CO3)2 (aq)

 

 

 

5. LiOH (aq) + H3PO4 (aq)

 

 

 

6. Na2CO3 (aq) + HCl (aq)

 

Video:
http://www.youtube.com/watch?v=gtcE8TosEq4

 

 

Note for Chapter-5H1:
Neutralization ion Exchange Reaction:

1.     When an acid reacts with a base, salt plus water are the products

 

Gas Forming Ion Exchange Reactions:

2.     When either H2SO3; H2CO3 or NH4OH is formed as a product it immediately

decomposes thus demonstrating a gas forming reaction.

 

3.     Most books do not show either H2CO3 or NH4OH as products, just the

decomposed products of the gases and water in the answer.

 

If H2CO3 is a predicted product in ion exchange, it is written as

CO2 and H2O.

 

For example:

Na2CO3 (aq) + HCl (aq) [H2CO3](aq) + NaCl (aq)

 

Should be written:

Na2CO3 (aq) + HCl (aq) CO2(g) + H2O (l) + NaCl (aq)

 

Two other products which are shown differently:

[NH4OH] NH3 + H2O

 

[H2SO3 ] SO2 + H2O

 

 

reactions

 


 

 

Chapter 5 Homework Packet

 

Chapter 5: Part W Rewriting Equations Ionically 2 points Plus additional homework

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)

 

 

 

 

Video:

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

Chapter 5 Homework Packet

 

Chapter 5 Part R: Redox Equations 2 points plus additional homework

 

Balance the following redox equations written in net ionic form:

Acid Media: (1 point)

 

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

 

 

 

 

 

half equation:

 

 

 

 

 

 

half equation:

 

 

 

 

 

 

Basic Media (1 point)

 

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

 

 

 

 

half equation:

 

 

 

 

 

half equation:

 

 

 

 

 

 

Separate Handouts and Additional Homework for Parts R & W will be distributed