Materials Unit
Chapter B
By Mr. Deitsch & Mrs. Tashlein for
SASD ChemComm students
Chemical Shorthand (Review)
 Subscripts – # of that atom in 1 molecule
 Coefficients – # of molecules
 + means – “and” “with”
  means – “reacts to form” “yields” etc
 Social Elements – Cannot be alone
Chemical Shorthand (Review)
 Phase Symbol – Shows phase as: Formula(phase)

(s) – solid
Ex: metals, ionic compounds

(l) – liquid
Ex: H2O, Br2, Hg

(g) – gas
Ex: most social (O2, H2, etc)

(aq) – aqueous Ex: dissolved in water, acids
Law of Conservation (Review)
 Matter cannot be created nor destroyed,
but may be moved and changed
 # of atoms reacted =
# of atoms produced
 Balanced Equations maintain the Law.
Balancing Chemical
Equations: Concepts
Essential Knowledge
Answer the following In groups
1. State the Law of Conservation
Matter cannot be created nor destroyed, only changed and moved
2. Using the law of conservation, explain why the
following reaction is wrong:
HCl + NaOH  NaCl
No H or O in Products (implies that they were destroyed)
3. How can you tell when an equation is balanced?
# and Type of atoms are equal before and after the arrow
HCl + NaOH  NaCl
Not Balanced
H & O destroyed?!?
2–H-0
1 - Cl - 1
1 - Na - 1
1-O-0
HCl + NaOH  NaCl + H2O
2-H-2
Balanced 1 - Cl - 1
same # & type on
both sides
1 - Na - 1
1 - O -1
Answer the following In groups
4. Consider the balanced reaction between iron metal & water:
3 Fe + 4 H2O  Fe3O4 + 4 H2
a)
Is the 3 in “ 3 Fe ” a subscript or a coefficient?
b)
What does the subscript in the water molecule mean?
That there are 2 Hydrogens in each molecule of water
What does “ 4 H2O ” actually tell in this reaction? Draw it.
4 molecules of Water
H2 O
H2 O
H2O
H2 O
How does changing a coefficient differ from changing a subscript?
See Next Slide
Why is Fe balanced as 3 Fe instead of Fe3?
3 Fe affects amount, Fe3 changes what it is.
c)
d)
e)
How does changing a coefficient differ from changing a
subscript?
Coefficient
Subscript
 # of molecules
 # atoms per molecule
 Changes Amount
 Changes Identity
 How much there is.
 Used for Balancing
 What the chemical is.
 Used for Bonding
Since it changes the Identity,
NEVER change SUBSCRIPTS when Balancing
Answer the following In groups
5. How is balancing a chemical reaction
related to the law of conservation of
checks that the same amount and type of atoms
matter? Balancing
are present before and after the arrow, making sure that
no matter was created nor destroyed.
6. What do the 4 and 2 signify in 4 H2? How
many Hydrogen atoms are there?
4 – Four molecules of Hydrogen Gas
2 – Two atoms of Hydrogen per gas molecule
Total – 8 atoms of Hydrogen in the entire formula
Use the Equation to answer the ?s
2 Al(NO3)3 + 3 FeCl2  3 Fe(NO3)2 + ____ AlCl3
2 – Al - 1
6-N-6
18 - O - 18
3 - Fe - 3
6 - Cl - 3
7. Perform an Atom Inventory
a.Is it balanced? Explain:
No, the # of Al & Cl are different
b.What Coefficient could be put in the blank to
make this equation balanced? 2
Use the Equation to answer the ?s
2 Al(NO3)3 + 3 FeCl2  3 Fe(NO3)2 + 2 AlCl3
a.Write the Names of the Reactants in this eqn:
Aluminum Nitrate
Iron (II) Chloride
b.Write the Names of the Products in this eqn:
Iron (II) Nitrate
Aluminum Chloride
Answer the following In groups
8. What should you do if an equation you
have written cannot be balanced?
Check subscripts and Rewrite it
9. How would you indicate the physical state
of a reactant or product in a chemical
equation?
Phase Symbols(aq)
Answer the following In groups
10. a)
Pure calcium when reacted with rust (Iron
[III] Oxide) under a great deal of heat will
yield pure iron & calcium oxide
Translate and Balance
Answer the following In groups
b)
Iron metal can be obtained by reacting the
solid ore hematite, Fe2O3, with solid carbon,
also producing carbon dioxide gas
Translate and Balance;
include Phase Symbols(aq)
Balancing Chemical Equations:
Basic
Essential Skill
Rem: Translating Chemical Eqns
1. Skim for Direction
2. Translate Word/Phrase into chemistry
3. Check Problems:

Symbols used correctly: [+] and []

Social elements are not alone.

Check compounds. (Charge = 0)

Make sure all phases are correct.
4. Balance
Balancing Equations (Steps)
1.
Pick an Element (normally the first one).
2.
Check BOTH sides of the  to see if the
amount of that element is equal.
3.
If Not, change Coefficients until they are.
(DO NOT CHANGE SUBSCRIPTS)
4.
Repeat until all elements are balanced.
5.
Make sure Coefficients are in lowest terms.
Demonstration
BALANCED
!
NOT BALANCED
!
BALANCED !
Mg(s) + 2 NaCl(aq)  MgCl2 (aq) +2 Na(s)
NOT
BALANCED
BALANCED
! !
Basic Balancing
The Law of Conservation states that we
cannot get something from nothing and we
cannot completely eradicate matter.
In balancing chemical equations, we follow
the Law of Conservation and then can
accurately predict what is going to happen
in nature anyway.
Example # 1
__ CCl4 + __ Zn3P2  __ C3P4 + __ ZnCl2
Example # 2
Use the following equation to prove the Law
of Conservation:
 Proof
 Explain
 Relate
2 Ca + O2  2 CaO
2 – Ca - 2
2-O–2
All atoms are equal before and after the arrow,
showing that no matter was created or destroyed,
thus upholding the Law of Conservation
Example # 3
Aqueous Magnesium Chloride and solid
Iron are produced from Magnesium metal
and Iron (III) Chloride dissolved in water.
1.
2.
3.
4.
Skim for Direction
Translate Word/Phrase
Check for Problems
Balancing
Basic Practice (Balancing)
2 H3P  __
3 H2 + __P
2
__
6 NaCl + __ Ca3N2  __
2 Na3N + __
3 CaCl2
__
2 K3P + 3
3 K 2S
__
__ MgS  __ Mg3P2 + __
Basic Practice (Conservation)
Use the following equation to prove the Law
of Conservation:
 Proof
2 MgS + CH4  CS2 + 2 MgH2
 Explain
 Relate
2 – Mg - 2
2–S-2
1–C-1
4-H–4
All atoms are equal before and after the arrow,
showing that no matter was created or destroyed, thus
upholding the Law of Conservation
End of Day 1
 Overview
 Reviewed Chemical
Shorthand
 Balancing Concepts
 Begin Basic
Balancing
 Homework
 Finish Balancing 1-12
 Review Translations
Basic Practice (Word Problem)
Solid Carbon burns in Oxygen to form
Carbon Dioxide gas
Basic Balancing Review
3 Cl2 + __
2 Al  2
__
__ AlCl3
2 H2O + 2__ Br2  __
4 HBr + __ O2
__
__
3 MgBr2 + __
2 GaP  __ Mg3P2 + __
2 GaBr3
Balancing Chemical
Equations: Advanced
Essential Skill
Advanced Balancing: 3+ times
Sometimes the same element is found in
multiple reactants or products.
This is harder to do and should be
balanced last to see if it balances itself as
the other parts are dealt with.
If not, take notes, marking how many of
that element is in each compound.
Hint # 1
Shows up a lot, do LAST!!!
__ C4H10O + __ O2  __ CO2 + __ H2O
1st Carbon (C) = 4 on left, 1 on right
Make both equal to “4” w/ Coefficients
2nd Hydrogen (H) = 10 on left, 2 on right
Make both equal to “10” w/ Coefficients
Last Oxygen (O) = what do you have now on L / R?
Make both equal by adding necessary Coefficient(s)
Advanced Multi-Practice
__ CH4 + __ O2  __ CO2 + __ H2O
__ C4H12 + __ O2  __ CO2 + __ H2O
__ C4H10O + __ O2  __ CO2 + __ H2O
A Problem:
Al(NO3)3 + FeSO4  Fe(NO3)2 + Al2(SO4)3
 Too many Oxygens to count easily…
 Treat NO3 as “Nitrate” and SO4 as “Sulfate”
instead of separating the elements
 Box them and count the boxes
__Al(OH)
2
3 2SO4(aq)  __Al2(SO4)3(aq) + __H
6 2O(l)
3(s) + __H
2 1 – Al – 2
18 10 7 – O – 13 18
12 8 5 – H – 2 12
3 1–S– 3
__Al(OH)
2
3 2SO4(aq)  __Al2(SO4)3(aq) + __H
6 2O(l)
3(s) + __H
2 1 – Al – 2
6 3 –O– 1 6
12 8 5 – H – 2 12
3 1 – SO4 – 3
Hint # 2
Polyatomic Ions are multiple elements
acting as one ion.
SO4 = Sulfate
Treat them as one thing when balancing.
Place a Box around the entire polyatomic
(and required subscripts)
Al2(SO4)3
The same polyatomic must appear on both
sides of the equation for this to work.
A Shortcut:
Al(NO3)3 + FeSO4  Fe(NO3)2 + Al2(SO4)3
Too many Oxygens to count easily…
Treat NO3 as “Nitrate” and SO4 as “Sulfate”
instead of separating the elements
Box them and count the boxes
A Boxing Demo:
2 Al(NO3)3 + 3 FeSO4  3 Fe(NO3)2 + Al2(SO4)3
3 Nitrates on the left, 2 on the right, so…

Make them both Six (6) with Coefficients
1 Sulfate on the left, 3 on the right, so…

Make them both Three (3) with Coefficients
Tada!!! Everything’s BALANCED!!!
Example # 2
__ AlPO4 + __ Zn(HCO3)2  __ Zn3(PO4)2 + __ Al(HCO3)3
End of Day 2
 Overview
 Reviewed Balancing
Concepts
 Homework
 Finish Advanced
Problems 1-15
 Reviewed Translation
 Advanced Balancing
Tips (Boxing)
 Special Note
 Do Take-Home Quiz
over Break!
Advanced Balancing Review
__ H3PO4 + __ CaO  __ Ca3(PO4)2 + __ H2O
___ C6H12 + ___ O2  ___ CO2 + ___ H2O
__ Al2(SO3)3 + __ NaNO3  __ Na2SO3 + __ Al(NO3)3
___ C5H14O3 + ___ O2  ___ CO2 + ___ H2O
Advanced Polyatomic Practice
__ K3PO3 + __ MgS  __ Mg3(PO3)2 + __ K2S
__ K2CrO4 + __ AlCl3  __ Al2(CrO4)3 + __ KCl
__ Al(CN)3 + __ FeCO3  __ Fe(CN)2 + __ Al2(CO3)3
Class Practice with Flipchart
Practice mini-quiz
End of Day 3
 Overview
 Reviewed Balancing
 Flipchart practice
 Homework
 Take Home Quiz
Balancing Chemical
Equations: Expert
Essential Skill
More than Four
There are rxns with more than four blanks.
These may be longer but they are solved
the exact same way as easier problems.
B o x
Polyatomics
F l a g
Difficult elements
However, because it is longer, it is easier
to make mistakes. Take Notes & Go Slow
Example
___V(NO3)5 + ___MgCO3  ___CO2 + ___V2O5 + ___Mg(NO3)2
Expert: More than Four
__ Na2CO3 + __ H2  __ Na + __ CO2 + __ H2O
__Li + __CO + __ H2O  __ Li2CO3 + __ H2
__Al2(CO3)3 + __Na  __Na2O + __CO2 + __Al
Odd-Even Split
You are almost done an equation when…
 One side of the arrow has an odd number
and the other has an even number.
 The easiest way to solve this is to double
all the coefficients you have already used.
 Remember all “1 s” that you assumed.
21 5H10 +15
5 2 +10
5 2O
__C
__O2 10
__CO
__H
10 5 – C – 1 5 10
20 10 – H – 2 10 20
30 2 – O – 3 11 15 30
Wait! We have a problem…
For Odd-Even Splits, DOUBLE!!!
Expert: Odd-Even Splits
__ C4H6 + __ O2  __ CO2 + __ H2O
__ C7H18 + __ O2  __ CO2 + __ H2O
__ C3H8O + __ O2  __ CO2 + __ H2O
End of Day 4
 Overview
 Homework
 Reviewed Advanced
 Combined # 1-24
 Intro Expert


5+ ____ Blanks

Odd-Even Splits

Practice Expert 1-20
 Practice Mini-Quiz
Study for Balancing
Mini-Quiz in class
tomorrow
Expert Balancing Review
__ C5H6 + __ O2  __ CO2 + __ H2O
___CaCO3 + ___H3PO4 
___H2O + ___CO2 + ___ Ca3(PO4)2
__ C5H12O + __ O2  __ CO2 + __ H2O
Reaction Types
 Chemical Reactions can be grouped
according to their reactants & products.

Useful in Predicting Products
 We are going to focus on the
five (5) most important reaction
types for general chemistry.
Synthesis (combine)
 Many Reactants become 1 Product
 Brief:
A + B  AB
 Ex: Burning Aluminum
[S]
Decomposition (break apart)
[D]
 1 Reactant becomes many Products
 Brief:
AB  A + B
 Ex: Carbonate natural breakdown into CO2
H2CO3  H2O + CO2
Al2(CO3)3  Al2O3 + 3 CO2
Combustion (burn)
[C]
 Hydrocarbon and Oxygen burn to make
Carbon Dioxide and Water
 Brief:
CxHx + O2  CO2 + H2O
 Ex: Burning most Fuels
Single Replacement
[SR]
 Pure metal replaces a metal in solution
 Brief:
A + BX  AX + B
 Ex: Pure Zinc replacing Copper in solution
Zn + CuCO3  ZnCO3 + Cu
Visual
Zn + CuCO3  ZnCO3 + Cu
Activity Series
List of metals by reactivity
 Most Reactive at the top
 Least Reactive at the bottom
Won’t work unless the pure metal
is more reactive (higher up) than
the bonded metal
Double Replacement
[DR]
 Metals switching with each other in
solution, often makes a precipitate.
 Brief:
AX + BY  AY + BX
 Ex: Silver solution switching with copper in solution
and making a solid silver precipitate.
AgNO3(aq) + CuCl2(aq)  Cu(NO3)2(aq) + 2 AgCl(s)
Overview
 Synthesis:
A + B  AB
 Decomposition:
AB  A + B
 Combustion:
CxHx + O2  CO2 + H2O
 Single Replace:
A + BX  AX + B
 Double Replace:
AX + BY  AY + BX
Examples
C
2
5
DR 3
2
D
2
2
4
3
SR
6
2
3
2
S
4
6
6
2
Other Reactions
 RedOx: Showing the transfer of electrons
 Hydrolysis: Splitting compounds w/ Water
 Condensation: Combing compounds and
releasing water.
 Electrolysis: Splitting compounds with
electricity.
 Neutralization: Acid + Base = Salt + Water
End of Day 5
 Overview
 Reviewed Expert
 Combined Practice
 Reaction Types

Identification
 Homework
 Identifying Reaction
Types (w/ Balancing)
#1-16
Mr. Guch's Handy Checklist for figuring out what type
of reaction is taking place:
Follow this series of questions. When you can answer "yes" to a question, then stop!
1.
Does your reaction have oxygen as one of it's reactants and carbon dioxide and water
as products? If yes, then it's a combustion reaction
2. Does your reaction have two (or more) chemicals combining to form one chemical? If
yes, then it's a synthesis reaction
3. Does your reaction have one large molecule falling apart to make several small ones?
If yes, then it's a decomposition reaction
4. Does your reaction have any molecules that contain only one element? If yes, then it's
a single replacement reaction
5. Does your reaction have water as one of the products? If yes, then it's an acid-base
reaction
6. If you haven't answered "yes" to any of the questions above, then you've got a double
replacement reaction
Predicting Synthesis
1. Translate Reactants and Combine into One
Product (cation-anion)
2. Fix it!
 Check Charges using subscripts
 Check Diatomics (Social elements), i.e. H2
3. Balance
Synthesis of Sodium and Oxygen
Do 1-5 in packet
Predicting Combustion
1. Copy parts that are ALWAYS in Combustion
 ___ _______ + ___ O2  ___CO2 + ___H2O
2. Fill in hydrocarbon from problem
3. Balance
Combustion of C₂H₆O
Do 6-9 in packet
Reactivity
 Some metals are more reactive than others.
 In the Demo, which was the most reactive?
 How could you tell?
 Will it be found pure or combined in nature?
 We can see this in how they react to water, air,
acids, or with anions.
 Refer to Activity Series (back of P.T)
Which is Most Reactive?
Ba – Cd – H
Ag – Au – Al
Mn – Mg – Ni
Hg – Mg – Sn
Sn – H – Pb
K – Sb – Li
Why it matters…
More reactive pure metals WILL REPLACE
less reactive metals bonded in solution.
Zn + CuCO3  ZnCO3 + Cu
Why it matters…
[part II)
Less reactive metals WILL NOT REPLACE
more reactive metals bonded in solution.
Cu + ZnCO3 
NR
Will it Work?
Lithium replacing Hydrogen
Lead replacing Nickel
Cadmium replacing Iron
Lead replacing Copper
Barium replacing Calcium
Silver replacing Gold
Will it Work?
Ba + KNO3 
Ag + CaSO4 
Mg + ZnCl2 
Na + Al(NO3)3 
Hg + CuNO3 
Mn + H2SO4 
Reactivity and Predicting SR
Circle most reactive element
Answer 1-15 in packet
Final Skill – Predicting Rxns
1. Does it Work?
 YES = Switch Metals, make Skeleton
 NO = NR
2. Fix it!
 Re-Cancel Charges & Check Social (H2)
3. Balance
Single Replacement Examples
___ K + ___ Fe2(SO4)3 
___ Ag + ___ Na2S 
___ Cd + ___ HCl 
Predicting Single Practice
___ Li + ___ K2O 
___ Pb + ___ CaBr2 
___ Mg + ___ H3PO4 
Predicting SR Practice
Predict and balance 16-22 in packet.
Demonstration
Mg(s) + 2 NaCl(aq)  MgCl2 (aq) + 2 Na(s)
BALANCED !
1 – Mg – 1
BALANCED !
1 – Na – 1
1 – Cl – 2
BALANCED !
2 2 (s)  __CS2 (s) + __SCl
2
__CCl4 (aq) + __S
2(aq)
1 –C– 1
4 – Cl – 2 4
4 2– S– 3 4
2
2
3
__KClO

__KCl
+
__O
(s)
(s)
3
2 (g)
2 1– K – 1 2
2 1 – Cl – 1 2
6 3– O – 2 6