Transcript Chemical Equations plus Reactions

Types of Reactions
Types of Reactions
•
There are five types of chemical
reactions we will talk about:
1.
2.
3.
4.
5.
•
Synthesis reactions
Decomposition
_____________ reactions
Single displacement reactions
Double
displacement reactions
__________________
Combustion reactions
You need to be able to:
identify the type of reaction
predict the product(s) [honors only]
Synthesis Reactions
Direct combination reaction (Synthesis)
2 Na
+
Na
Cl2
Cl
Cl

2 NaCl

Na
General form: A
element or
compound
+
B
element or
compound

AB
compound
Synthesis Reactions
reactant + reactant  1 product
•
Example: 2H2 + O2  2H2O
•
Example: C + O2  CO2
Synthesis Reactions
Synthesis Reactions
Photosynthesis
6 CO2 + 6 H2O
C6H12O6 +
Formation of water
2 H2 + O2
2 H2O
Formation of salt
2 Na + Cl2
2 NaCl
General Form
A + B
C
6 O2
Honors Practice
•
•
•
•
Predict the products. Write and balance
the following synthesis reaction equations.
Sodium metal reacts with chlorine gas
2 Na(s) + Cl2(g)  2 NaCl(g)
Solid Magnesium reacts with fluorine gas
Mg(s) + F2(g)  MgF2(s)
Aluminum metal reacts with fluorine gas
2 Al(s) + 3 F2(g)  2 AlF3(s)
Decomposition Reactions
Decomposition reaction
2 H2 O
2 H2
+
O2
H
O
H
+
H
O
H
General form: AB
compound
A
+
B
two or more elements
or compounds
Decomposition Reactions
1 Reactant  Product + Product
•
Example: 2 H2O  2H2 + O2
•
Example: 2 HgO  2Hg + O2
Decomposition Reactions
Decomposition Reactions
Hydrogen Peroxide
2 H2O2
2 H2O
+
2 H2
+
O2
Electrolysis of water
2 H2O
electricity
O2
Nitrogen triiodide
2 NI3
N2
+ 3 I2
General Form
AB
A + B
Decomposition Exceptions
[Honors]
•
Carbonates and chlorates are special case
decomposition reactions that do not go to
the elements.
•
Carbonates (CO32-) decompose to carbon
dioxide and a metal oxide
•
•
Chlorates (ClO3-) decompose to oxygen gas
and a metal chloride
•
•
Example: CaCO3  CO2 + CaO
Example: 2 Al(ClO3)3  2 AlCl3 + 9 O2
There are other special cases, but we will not
explore those in this class.
Practice
•
•
•
Predict the products. Then, write and
balance the following decomposition
reaction equations:
Solid Lead (IV) oxide decomposes
PbO2(s)  Pb(s) + O2(g)
Aluminum nitride decomposes
2 AlN(s)  2 Al(s) + N2(g)
Honors Practice
Identify the type of reaction for each of the
following synthesis or decomposition
reactions, and write the balanced equation:
N2(g) + O2(g)  Nitrogen monoxide
BaCO3(s) 
Co(s)+ S(s)  (make Co be +3)
NH3(g) + H2CO3(aq) 
NI3(s) 
Solutions
N2(g) + O2(g)  2 NO(g) synthesis
BaCO3(s)  Ba(s) + CO3(g) decomposition
2 Co(s)+ 3 S(s)  Co2S3(s) synthesis
2 NH3(g) + H2CO3(aq)  (NH4)2CO3(s) synthesis
2 NI3(s)  N2(g) + 3 I2(s) decomposition
Single and Double Replacement
Reactions
Single-replacement reaction
Mg
+
CuSO4
General form:
A
+ BC

MgSO4

AC
+
+
Cu
B
Double-replacement reaction
CaCO3
+
General form:
AB
+
2 HCl

CaCl2
+
H2CO3
CD

AD
+
CB
Single Replacement Reactions
•
•
•
Single Replacement Reactions occur when
one element replaces another in a compound.
A metal can replace a metal (+) OR
a nonmetal can replace a nonmetal (-).
element + compound product + product
A + BC  AC + B (if A is a metal) OR
A + BC  BA + C (if A is a nonmetal)
(remember the cation always goes first!)
When H2O splits into ions, it splits into
H+ and OH- (not H+ and O-2 !!)
Single Replacement Reactions
Printable
Version
of
Activity
Series
Activity Series
Element Reactivity
Ca
Foiled again –
Aluminum loses to Calcium
Li
Rb
K
Ba
Ca
Na
Mg
Al
Mn
Zn
Cr
Fe
Ni
Sn
Pb
H2
Cu
Hg
Ag
Pt
Au
Halogen Reactivity
F2
Cl2
Br2
I2
Activity Series of the elements




Activity series – list of elements organized
according to the ease with which the
elements undergo certain chemical
reactions.
Used to predict if a reaction will take place
For metals – greater activity means loss of
electrons
For nonmetals – greater activity means
ease to gain electrons




Order of listing is usually determined by
single-replacement reactions
Most active element is placed at the top of
the series
An element can replace any element
below it on the series
An element cannot replace any element
above it on the series
Potassium reacts with Water
POW!
Predict if these reactions will occur
3 Mg
+ 2 AlCl3
2 Al
+ 3 MgCl2
Can magnesium replace aluminum? YES, magnesium is more reactive than aluminum.
Activity Series
Al
+
MgCl2
No reaction
Can aluminum replace magnesium? NO, aluminum is less reactive than magnesium.
Activity Series
MgCl2
+
Al
Therefore, no reaction will occur.
No reaction
Order of reactants
DOES NOT
determine how
they react.
The question we must ask is can the single element replace its counterpart?
metal replaces metal or nonmetal replaces nonmetal.
Single-Replacement Reactions
Activity Series
“Magic blue-earth”
Fe + CuCl2
FeCl2
+
Cu
Can Fe replace Cu? Yes
Zinc in nitric acid
Zn
+ 2 HNO3
Can Zn replace H?
Zn(NO3)2
+ H2
Yes
NO REACTION
MgCl2
+
Can Br replace Cl?
Br2
MgBr2
+
No
General Form
A
+
BC
AC + B
Cl2
Li
Rb
K
Ba
Ca
Na
Mg
Al
Mn
Zn
Cr
Fe
Ni
Sn
Pb
H2
Cu
Hg
Ag
Pt
Au
F2
Cl2
Br2
I2
Single Replacement Reactions
Write and balance the following single
replacement reaction equation:
• Zinc metal reacts with aqueous
hydrochloric acid
Zn(s) + 2 HCl(aq)  ZnCl2 + H2(g)
Note: Zinc replaces the hydrogen ion in the
reaction
•
Single Replacement Reactions
•
Sodium chloride solid reacts with fluorine gas
2 NaCl(s) + F2(g)  2 NaF(s) + Cl2(g)
Note that fluorine replaces chlorine in the compound
•
Aluminum metal reacts with aqueous copper
(II) nitrate
2 Al(s)+ 3 Cu(NO3)2(aq) 2 Al(NO3)3(aq) + 3 Cu(s)
Double Replacement Reactions
•
•
•
Double Replacement Reactions occur
when a metal replaces a metal in a compound
and a nonmetal replaces a nonmetal in a
compound
Compound + compound  product +
product
AB + CD  AD + CB
Double Replacement Reactions
•
•
•
Think about it like “foil”ing in algebra, first and
last ions go together + inside ions go together
Example:
AgNO3(aq) + NaCl(s)  AgCl(s) + NaNO3(aq)
Another example:
K2SO4(aq) + Ba(NO3)2(aq)  2 KNO3(aq) + BaSO4(s)
acetate
bromide
carbonate
chloride
chromate
hydroxide
iodide
nitrate
phosphate
sulfate
sulfide
TABLE OF SOLUBILITIES IN WATER
aluminum
s
aq
n
s
n
s
aq
aq
s
aq
d
ammonium
aq
aq
aq
aq
aq
aq
aq
aq
aq
aq
aq
barium
aq
aq
s
aq
s
aq
aq
aq
s
s
d
calcium
aq
aq
s
aq
aq
ss
aq
aq
s
s
d
copper (II)
aq
aq
s
aq
s
s
n
aq
s
aq
s
iron (II)
aq
aq
s
aq
n
s
s
aq
s
aq
s
iron (III)
aq
aq
n
aq
s
s
n
aq
s
s
d
lead
aq
s
s
ss
s
s
s
aq
s
s
s
magnesium
aq
aq
s
aq
aq
s
aq
aq
s
aq
d
mercury (I)
s
s
s
s
s
n
s
aq
s
s
si
mercury (II)
aq
s
s
aq
s
s
s
aq
s
d
si
potassium
aq
aq
aq
aq
aq
aq
aq
aq
aq
aq
aq
silver
s
s
s
s
s
n
s
s
s
s
s
sodium
aq
aq
aq
aq
aq
aq
aq
aq
aq
aq
aq
zinc
aq
aq
s
aq
aq
s
aq
aq
s
aq
s
Legend
s = solid
aq = aqueous
d = decomposes
n = not isolated
Solubility Rules
1.
Most nitrates are soluble.
2.
Most salts containing Group I ion and ammonium ion, NH4+, are soluble.
3.
Most chloride, bromide, and iodide salts are soluble, except Ag+, Pb2+
and Hg22+.
4.
Most sulfate salts are soluble, except BaSO4, PbSO4, Hg2SO4, and CaSO4.
5.
Most hydroxides except Group 1 and Ba(OH)2, Sr(OH)2, and Ca(OH)2 are
only slightly soluble.
6.
Most sulfides, carbonates, chromates, and phosphates are only slightly
soluble.
Ohn-Sabatello, Morlan, Knoespel, Fast Track to a 5 Preparing for the AP Chemistry Examination 2006, page 91
Find the precipitate
1.
2.
3.
4.
5.
HCl(aq) + AgNO3(aq)  HNO3( ) + AgCl( )
3 CaCl2(aq) + 2 Na3PO4(aq)  Ca3(PO4)2( ) + 6 NaCl(
Pb(NO3)2(aq ) + BaCl2( aq )  PbCl2( ) + Ba(NO3)2( )
FeCl3(aq) + 3 NaOH(aq)  Fe(OH)3( ) + 3 NaCl( )
H2SO4(aq) + Ca(OH)2(aq)  2 H2O( ) + CaSO4( )
6. 2 KOH(aq) + CuSO4(aq)  K2SO4(
)
+ Cu(OH)2(
)
)
Predict if these reactions will occur
2 HCl(aq) + Pb(NO3)2(aq)  2 HNO3( aq
?) + PbCl2( ?S )
Will a precipitate form? Yes, so the reaction will take place.
NH4OH(aq) + CaSO4(aq) 
Don’t
forget to
balance the
equation
(NH
)2SO4( aq?) + Ca(OH)2( aq
No 4reaction
?)
Will a precipitate form? No, so the reaction will not take
place.
Formation of a solid: AgCl
AgNO3(aq) + KCl(aq)  KNO3 (aq) + AgCl(s)
lead (II) chloride + potassium iodide
K1+
Pb2+ Cl1PbCl2
+
I1-
KI
Copyright © 2007 Pearson Benjamin Cummings. All rights reserved.
potassium chloride + lead (II) iodide
Pb2+ Cl1KCl (aq)
K1+
+
I1-
PbI2 (ppt)
Practice
•
Predict the products. Balance the equation
5.
HCl(aq) + AgNO3(aq) 
CaCl2(aq) + Na3PO4(aq) 
Pb(NO3)2(aq) + BaCl2(aq) 
FeCl3(aq) + NaOH(aq) 
H2SO4(aq) + NaOH(aq) 
6.
KOH(aq) + CuSO4(aq) 
1.
2.
3.
4.
Solutions
•
Predict the products. Balance the equation
5.
HCl(aq) + AgNO3(aq)  HNO3(aq) + AgCl(s)
3 CaCl2(aq) + 2 Na3PO4(aq)  Ca3(PO4)2(s) + 6 NaCl(aq)
Pb(NO3)2(aq) + BaCl2(aq)  PbCl2(s) + Ba(NO3)2(aq)
FeCl3(aq) + 3 NaOH(aq)  Fe(OH)3(s) + 3 NaCl(aq)
H2SO4(aq) + Ca(OH)2(aq)  2 H2O(l) + CaSO4(s)
6.
2 KOH(aq) + CuSO4(aq)  K2SO4(aq) + Cu(OH)2(s)
1.
2.
3.
4.
Combustion Reactions
•
•
Combustion reactions
occur when a hydrocarbon
reacts with oxygen gas.
This is also called
burning!!! In order to burn
something you need the 3
things in the “fire
triangle”:
1) A Fuel (hydrocarbon)
2) Oxygen to burn it with
3) Something to ignite the
reaction (spark)
Combustion Reactions
•
•
•
In general:
CxHy + O2  CO2 + H2O
Products in combustion are
ALWAYS carbon dioxide and
water. (although incomplete
burning does cause some byproducts like carbon monoxide)
Combustion is used to heat
homes and run automobiles
(octane, as in gasoline, is C8H18)
Combustion
Reactions
Edgar Allen Poe’s drooping
eyes and mouth are potential
signs of CO poisoning.
Combustion
•
Example
•
•
C5H12 + 8 O2  5 CO2 + 6 H2O
Write the products and balance the
following combustion reaction:
•
C10H22 + O2  CO2 + H2O
21
C10H22 + 2 O2  10 CO2 + 11 H2O
2 C10H22 + 21 O2  20 CO2 + 22 H2O
Write a balanced chemical equation for the following combustion reactions:
A.
C5H12
+
8 O2

5 CO2
B.
C3H8
+ 5 O2

3 CO2
+ 4 H2O
C.
C15H28 + 22 O2

15 CO2
+ 14 H2O
+
6 H2O
Mixed Practice
•
1.
2.
3.
4.
5.
State the type, predict the products, and
balance the following reactions:
BaCl2 + H2SO4 
C6H12 + O2 
Zn + CuSO4 
Cs + Br2 
FeCO3 
Solutions
•
1.
2.
3.
4.
5.
State the type, predict the products, and
balance the following reactions:
BaCl2 + H2SO4  BaSO4 + 2 HCl
C6H12 + 9 O2  6 CO2 + 6 H2O
Zn + CuSO4  Cu + ZnSO4
2 Cs + Br2  2 CsBr
FeCO3  Fe + CO3