Oct 2013
Chapter 9 is where you will find most of this information
There are MANY types of Chemical reactions; we will start with a few
Reactants  Products
(Read as reactants react to form Products)
Some reactions take in energy and are “endothermic”
Some reactions give off energy and are “exothermic”
KNOW THE SEVEN DIATOMIC ELEMENTS!!!!!!!
( I2, Br2, Cl2, F2, O2, N2, H2)
Sometimes we use special symbols to indicate the phase of the
reactants. The ones you need to know are:
(s)
(l)
(g)
(aq)
for solid (precipitate)
for liquid
for a gas (bubbles)
for aqueous solutions (chemicals dissolved in water)
If a symbol for an element is placed above or below the reaction arrow it
indicated that that element is a catalyst. A catalyst doesn’t get used up or produced in
the reaction but by having that element present the rate of the reaction is increased.
There are two fundamental laws of nature we hope you are familiar with
- Matter cannot be created or destroyed (just moved around)
o This law has been replaced with:
- Energy cannot be created or destroyed (but will flow from areas of
higher energy to lower energy)
In chemistry it is easier to think of the first statement
We will also be studying the naming of chemical compounds some of the basic are:
*- Metals and metals form alloys
*- A metal and a non-metal form an ionic compound (aka a formula unit or salt)
*- A non-metal and a non-metal form a covalent molecule
Types of Chemical Reactions
Now that you know something about elements and compounds, lets see how they can react to for
different stuff! Just like with Lego’s (the snap together building blocks) you can put them
together, take them apart or swap them around.
1.
A DECOMPOSITION reaction starts with one reactant and ends up with two or
more products. Which of the following reactions are decomposition reactions? Circle
the letters.
a)
b)
c)
d)
e)
2.
NaCl  Na + Cl2
Na + Cl2  NaCl
H2O  H2 + O2
NaOH + HCl  HOH + NaCl
H2 + O2  H2O
A SYNTHESIS reaction starts with two reactants and ends up with one product.
Which of the following reactions are synthesis reactions? Circle the letters.
a)
b)
c)
d)
e)
3.
NaCl  Na + Cl2
Na + Cl2  NaCl
H2O  H2 + O2
NaOH + HCl  HOH + NaCl
K +Cl2  KCl
A SINGLE REPLACEMENT reaction starts with two reactants and ends up with
two products. The uncombined element takes the place of the combined element in the
compound. Which of the following reactions are single replacement reactions? Circle
the letters.
a)
b)
c)
d)
e)
4.
NaCl  Na + Cl2
NaOH + HCl  HOH + NaCl
K + AgCl2  Ag + KCl
Na + HCl  H2 + NaCl
H2O  H2 + O2
A DOUBLE REPLACEMENT reaction starts with two reactants and ends up with
two products. In this case both reactants are compounds and both products are
compounds. Which of the following reactions are double replacement reactions?
Circle the letters
a)
b)
c)
d)
e)
NaOH + HCl  HOH + NaCl
Na + HCl  H2 + NaCl
K + AgCl2  Ag + KCl
KOH + HNO3  KNO3 + HOH
Ca + S  CaS
5.
A COMBUSTION reaction is when the reactants are oxygen and a hydro carbon and
6.
the products are water and carbon dioxide.
A NEUTRALIZATION reaction is a special type of double replacement reaction that
will be covered in detail later on.
By now something should be bothering you about many of the Chemical
Equations listed above. Many of them ARE NOT BALANCED. Please follow the
teacher examples of how to balance equations.
Identifying and Balancing Chemical Equations
Name: _________________________________
period: ____
Balance these equations (even if the value is one put it in the blank) and identify
the type of reaction. (Synthesis, Decomposition, Single Replacement, Double Replacement or
Combustion)
Type of reaction
1. __HgO
__Hg + __O2
2. __ NaCl + __ AgNO3
3. __ Cl2 + __ Ca
____________
__NaNO3 + __AgCl
__ CaCl2
____________
____________
4. __ C2H6 + __ O2
__CO2 + __H2O
____________
5. __ H2O + __ Fe
__ Fe2O3 + __ H2
____________
6. __ Al2S3 + __Ca(OH)2
__ Al(OH)3 + __ CaS
____________
7. __ S8 + __ Fe
__ FeS
____________
8. __ N2 + __ H2
__ NH3
____________
__ KCl + __ O2
____________
9. __ KClO3
10. __ Al2(SO4)3 + __Ca(OH)2
__ Al(OH)3 + __ CaSO4 ____________
Chapter 9 in the Glencoe book we will be skipping the net ionic equation stuff for now)
Chapter 11 book problems: 1, 2, 3, 4, 11, 12, 14, 15, 18, 24, 28, 41, 49, 51, 54
Student notes on demo’s
Take notes on what you see happening to help you remember, is the reaction
exothermic or endothermic, how can you know that a chemical reaction has taken
place?
Single Replacement
Fe (s) + CuSO4 (aq)  Cu (s) + FeSO4(aq)
Double Replacement
2KI (aq) + Pb(NO3)2 (aq)  2KNO3 (aq) + PbI2 (s)
Synthesis
Zn (s) + I (s) [H2O]  ZnI2 + I2 (g)
(IN ‘DA HOOD, reaction takes place in the exhaust hood)
web example: http://www.youtube.com/watch?v=xT9V7Y1iKYc
(the water does not undergo a chemical change ( it might undergo a physical change to water vapor )but acts as a
catylist to speed up the reaction)
Decomposition (sugar decomposition catalyzed by very concentrated acid)
Web example: http://www.youtube.com/watch?v=DOb_BRydnCs
C12H22O11 + [H2SO4]  12C (s) + 11H2O + HEAT
2H2O2 (aq) [KI]  O2 (g) + 2H2O (l)
(Potassium Iodide does not undergo a change but acts as a catylist to speed up the reaction)
Types of Chemical Reactions with answers
Now that you know something about elements and compounds, lets see how they can react to for
different stuff! Just like with Lego’s (the snap together building blocks) you can put them
together, take them apart or swap them around.
1.
A DECOMPOSITION reaction starts with one reactant and ends up with two or
more products. Which of the following reactions are decomposition reactions? Circle
the letters.
a)
b)
c)
d)
e)
2.
NaCl  Na + Cl2
Na + Cl2  NaCl
H2O  H2 + O2
NaOH + HCl  HOH + NaCl
H2 + O2  H2O
A SYNTHESIS reaction starts with two reactants and ends up with one product.
Which of the following reactions are synthesis reactions? Circle the letters.
a)
b)
c)
d)
e)
3.
NaCl  Na + Cl2
Na + Cl2  NaCl
H2O  H2 + O2
NaOH + HCl  HOH + NaCl
K +Cl2  KCl
A SINGLE REPLACEMENT reaction starts with two reactants and ends up with
two products. The uncombined element takes the place of the combined element in the
compound. Which of the following reactions are single replacement reactions? Circle
the letters.
a)
b)
c)
d)
e)
4.
NaCl  Na + Cl2
NaOH + HCl  HOH + NaCl
K + AgCl2  Ag + KCl
Na + HCl  H2 + NaCl
H2O  H2 + O2
A DOUBLE REPLACEMENT reaction starts with two reactants and ends up with
two products. In this case both reactants are compounds and both products are
compounds. Which of the following reactions are double replacement reactions?
Circle the letters.
a)
b)
c)
d)
e)
NaOH + HCl  HOH + NaCl
Na + HCl  H2 + NaCl
K + AgCl2  Ag + KCl
KOH + HNO3  KNO3 + HOH
Ca + S  CaS
5.
A COMBUSTION reaction is when the reactants are oxygen and a hydro carbon and
6.
the products are water and carbon dioxide.
A NEUTRALIZATION reaction is a special type of double replacement reaction that
will be covered in detail later on.
By now something should be bothering you about many of the Chemical
Equations listed above. Many of them ARE NOT BALANCED. Please follow the
teacher examples of how to balance equations.
Identifying and Balancing Chemical Equations
Name: _______ANSWERS_________
period: ____
Balance these equations (even if the value is one put it in the blank) and identify
the type of reaction. (Synthesis, Decomposition, Single Replacement, Double Replacement or
Combustion)
Type of reaction
1. _2_HgO +
_2_Hg + _1_O2
2. _1_ NaCl + _1_ AgNO3
3. _1_ Cl2 + _1_ Ca
__Decomposition_
_1_NaNO3 + _1_AgCl
_1_ CaCl2
4. _2_ C2H6 + _7_ O2
_4_CO2 + _6_H2O
5. _3_ H2O + _2_ Fe
_1_ Fe2O3 + _3_ H2
6. 1 Al2(SO4)3 + 3 Ca(OH)2
_Double Replace_
___Synthesis___
__combustion___
_single replacement_
2 Al(OH)3 + 3 CaSO4 _Double Replace_
7. _1_ S8 + _8_ Fe
_8_ FeS
___ Synthesis __
8. _1_ N2 + _3_ H2
_2_ NH3
__ Synthesis __
9. _2_ KClO3
_2_ KCl + _3_ O2
10. 1 Al2(SO4)3 + 3 Ca(OH)2
__Decomposition_
2 Al(OH)3 + 3 CaSO4 __Double Replace_
Chapter 11 book problems: 1, 2, 3, 4, 11, 12, 14, 15, 18, 24, 28, 41, 49, 51, 54
Book problem answers:
1)
Solid sodium metal and liquid water react to form a solution of sodium hydroxide
and bubbles of hydrogen gas.
2)
S(s) + O2(g)  SO2 (g) but you might not know this
3)
a)
2 AgNO3 + H2S  Ag2S + 2 HNO3
b)
3 Zn(OH)2 + 2 H3PO4  Zn3(PO4)2 + 6 H2O
4)
a)
b)
H2 + S  H2S
FeCl3 + Ca(OH)2  Fe(OH)3 + CaCl2
11)
a)
b)
Fe(s) + Cl2(g)  FeCl3(s)
Al2(CO3)3(s)  Al2O3(s) + CO2(g)
12)
a) 2 SO2 + O2  2 SO3
b) Fe2O3 + 3 H2  2 Fe + 3 H2O
c) 4 P + 5 O2  P4O10
d) 2 Al + N2  2 AlN
14)
3 Mg(s) + N2(g)  Mg3N2
15)
Complete and balance this decomposition reaction:
2 HI  H2 + I2
; remember diatomic elements (I Br Cl F O N H)
18)
Write the products of these double-replacement reactions. Then Balance
each equation.
a) 3 NaOH(aq) + Fe(NO3)3(aq)  Fe(OH)3(s) + 3 NaNO3
b) 3 Ba(NO3)2(aq) + 2 H3PO4(aq)  Ba3(PO4)2(s) + 6 HNO3(aq)
24)
28)
Classify and balance each:
a) 2 C3H6 + 9 O2  6 CO2 + 6 H20
b) 2 Al(OH)3  Al2O3 + 3 H2O
c) Li + O2  Li2O
d) Zn + 2 AgNO3  2 Ag + Zn(NO3)2
Write the balanced net ionic equation for this reaction. (as written)
Ca2+(aq) + OH-(aq) + H+(aq) + PO4-3(aq) 
Ca2+ + PO43-(aq) + H2O(l)
You just don’t write the stuff that is on both sides: so…
Ca2+(aq) + OH-(aq) + H+(aq) + PO4-3(aq) 
Ca2+ + PO43-(aq) + H2O(l)
Or simplified it is:
41)
combustion
decomposition
synthesis
single replacement
OH-(aq) + H+(aq) 
H2O(l)
Balance each :
a) a bb team:
C + 2 F + 2 G  CF2G2
b) a tricycle: F + 3 W + S + 2 P  FW3SP2
49)
reactions
Write a balanced equation for each of the following double replacement
a) H2C2O4(aq) + KOH(aq)  K2C2O4 + 2 HOH
b) CdBr2(aq) + Na2S(aq)  CdS(s) + 2 NaBr(aq)
51)
Write a balanced equation for the complete combustion of each compound
a) C4H8 + 6 O2  4 CO2 +4 H2O
b) C3H6O + 4 O2  3 CO2 + 3 H2O ; (the reactant also has oxygen)
54)
Write a net ionic equation for each of the following reactions.
a) 2 HCl(aq) + Ca(OH)2(aq)  CaCl2 + 2 HOH
as ions it is written as:
2 H+ + 2Cl- + Ca2+ + 2(OH)-  Ca2+ + 2Cl- + 2H2O ; water’s
a molecule not an ionic compound
Cross out the ions that are on both sides gives us:
2 H+ + 2Cl- + Ca2+ + 2(OH)-  Ca2+ + 2Cl- + 2H2O
Or 2 H+ + 2(OH)-  2H2O ( the net ionic equation)
b) AgNO3(aq) + AlCl3(aq)  silver chloride is a precipitate
so… 3 AgNO3(aq) + AlCl3(aq)  3 AgCl(s) + 1 Al(NO3)3(aq)
as ions it is:
3 Ag+ + 3 (NO3)-(aq) + Al3+ + 3Cl-(aq)  3 AgCl(s) + 1 Al3+ + 3(NO3)-(aq)
Cross out the same ones to get net ionic:
3 Ag+ + 3 (NO3)-(aq) + Al3+ + 3Cl-(aq)  3 AgCl(s) + 1 Al3+ + 3(NO3)-(aq)
Or simply:
3 Ag+
+ 3Cl-(aq)  3 AgCl(s) (the net ionic equation)