Download Day 72 TYPES OF CHEMICAL REACTIONS

Movie: types of chemical reactions:
http://www.youtube.com/watch?v=i-HHvx1VC_8
Day 72
Identify, give evidence for, predict products of, and
classify the following types of chemical reactions:
1. Synthesis (combination)
2. Decomposition
3. Single Replacement
4. Double Replacement
5. Neutralization (acid/base)
6. Combustion
Synthesis
Decomposition
Single displacement
Double displacement
Neutralization
Combustion
Types of Chemical Reactions Foldable
1. Take 3 pieces of paper and stagger them about ¾ “-1”.
2. Flip over so that the staggered layers are at the bottom of
working area.
3. Fold top layers down from top – bottom while keeping the
staggered layers somewhat consistent.
4. Crease fold well, then fold over about a ½” and staple 2-3
staples across the crease to hold together.
5. Label each tab with a different reaction type.
6. On the inside: split the pages in half with a line down the
center
a) write a description of the reaction type on the left side
b) an example of that type of reaction using
elements/compounds and an example of the reaction
type using the letters A, B, C and/or D on the right
c) And three examples of the reaction
A chemical change: any change in which a new
substance is formed.
Evidence of a Chemical Change:
 Release of energy as heat
 Release of energy as light
 Change in colour
 Formation of a gas
 Change in odour…
• Chemical reactions result in chemical
changes.
– Chemical changes occur when new substances
are created.
– The original substance(s), called reactants,
change into new substance(s) called products.
Reactants
(c) McGraw Hill Ryerson 2007
Products
See pages 202 - 203
• Chemical reactions can be written in different
ways.
– A word equation:
• Nitrogen monoxide + oxygen  nitrogen dioxide
– A symbolic equation:
• 2NO(g) + O2(g)  2NO2(g)
COEFFICIENTS
STATE OF MATTER
- Letters indicate the state of
each compound.
(aq) = aqueous/dissolved in
water
- Indicates how many of each
molecule there is.
(s) = solid
-: there are 2 molecules of NO.
(g) = gas
(c) McGraw Hill Ryerson 2007
( ) = liquid
1.
Neutralization: Acid(H) + Base(OH)  salt + H(OH)
2.
Combustion: AB + oxygen  CO2 + H2O
3.
Synthesis: A + B  AB
4.
Decomposition: AB  A + B
5.
Single displacement: A + BC  AC + B
6.
Double displacement: AB + CD  AD + CB
Synthesis reactions are also known as FORMATION reactions.
Two or more reactants (usually elements) join to form a
compound.
– A + B  AB
where A and B represent
elements
– The elements may form ionic
compounds, like…
– Sodium metal and chlorine
gas combine to form sodium
chloride.
– 2Na + Cl2  2NaCl
Sodium added to chlorine gas
See pages 258 - 259
(c) McGraw Hill Ryerson 2007
Types: Synthesis
Example C + O2
C + O O

O C O
C
C
O O
C
CC
O O
C C C C C C CC
C
General:
A + B  AB
OTHER EXAMPLES…
1. Elements that form ionic compounds:
Magnesium metal reacts with oxygen gas to
form magnesium oxide.
• 2Mg + O2  2MgO
2. Elements that form covalent compounds:
Nitrogen gas and oxygen gas join to form
dinitrogen monoxide.
• 2N2 + O2  2N2O
SYNTHESIS REACTION (iron + sulphur):
http://www.youtube.com/watch?v=A5H6DVe5FAI
(c) McGraw Hill Ryerson 2007
See pages 258 - 259
• Decomposition reactions are the opposite of
synthesis reactions.
– A compounds breaks down into two or more
products (often elements).
–AB  A + B
where A and B represent elements
1. Ionic compounds may decompose to produce
elements, like the following:
• Table salt, sodium chloride, can be broken down into
sodium metal and chlorine gas by melting salt at 800ºC
and running electricity through it.
• 2NaCl  2Na + Cl2
See page 260
(c) McGraw Hill Ryerson 2007
See page 260
(c) McGraw Hill Ryerson 2007
Types: Decomposition
Example: NaCl
Cl Na

General:
Cl
+
Na
AB  A + B
Types: Decomposition
Example 2HgO
O Hg

O Hg
General:
Hg
+
O O
Hg
AB  A + B
2. Covalent compounds may decompose into
elements, like the following:
• By running electricity through water, the water
molecules decompose into hydrogen and oxygen
gases.
• 2H2O  2H2 + O2
DECOMPOSITION
REACTION:
http://www.youtube.com/wa
tch?v=NddwtXEA_Ak
See page 260
(c) McGraw Hill Ryerson 2007
• Single displacement reactions replace
one element from a compound with
another element.
– A compound and an element react, and the
element switches places with part of the
original compound.
• A + BC  B + AC where A is a metal, or
• A + BC  C + BA where A is a non-metal
See page 261
(c) McGraw Hill Ryerson 2007
Types: Single displacement
Example: Zn + CuCl2
Cu
Cl
+
Cl
General:
Zn

Zn
Cl
+
Cu
Cl
AB + C  AC + B
1. When A is a metal:
• Aluminum foil in a solution of copper(II)
chloride produces solid copper and aluminum
chloride.
• 2Al + 3CuCl2  3Cu + 2AlCl3
2. When A is a non-metal:
• When fluorine is bubbled through a sodium
iodide solution, iodine and sodium fluoride are
produced.
• Fl2 + 2NaI  I2 + 2NaF
SINGLE REPLACEMENT:
http://www.youtube.com/watch?v=hKtynbVtMKc
• Double Displacement reactions swap
elements between 2 compounds that react
together to form two new compounds.
– Two compounds react, with elements switching
places between the original compounds.
AB + CD  AD + CB
See page 262
(c) McGraw Hill Ryerson 2007
See page 262
(c) McGraw Hill Ryerson 2007
Types: Double displacement
Example: MgO + CaS
Mg
+
O
General:
Ca
S

Mg
S
+
Ca
O
AB + CD  AD + CB
Two solutions react to form a precipitate (solid) and
another solution.
Ionic solution + ionic solution  ionic solution + ionic solid.
AB + CD  AD + CB
– When potassium chromate and
silver nitrate react, they form a red
precipitate, silver chromate, in a
solution of potassium nitrate.
– K2CrO4 + 2AgNO3  Ag2CrO4 + 2KNO3
silver chromate
DOUBLE REPLACEMENT:
http://www.youtube.com/watch?v=opY3FLrPTa4
(c) McGraw Hill Ryerson 2007
• Neutralization reactions occur when an acid
(most compounds starting with H) and a
base (most compounds ending in OH) react
to form a salt and water.
• Neutralization reactions are a type of
double replacement.
• Acid + base  salt + water
HX + MOH  MX + H2O
where X and M are elements
See page 263
(c) McGraw Hill Ryerson 2007
1. Sulfuric acid is used to neutralize calcium
hydroxide:
• H2SO4 + Ca(OH) 2  CaSO4 + 2H2O
2. Phosphoric acid helps to neutralize the
compounds that cause rust, such as iron(II)
hydroxide.
• H3PO4 + 3Fe(OH)2  Fe3(PO4)2 + 6H2O
NEUTRALIZATION:
http://www.youtube.com/watch?v=_P5hGzA6Vb0
See page 263
(c) McGraw Hill Ryerson 2007
• Combustion reactions occur when a
compound or element react with oxygen to
release energy and produce an oxide.
– Also sometimes referred to as hydrocarbon
combustion.
CXHY + O2  CO2 + H2O
where X and Y represent integers
METHANOL + oxygen:
http://www.youtube.com/watch?v=98JuJ-G1qXY&feature=related
See page 264
(c) McGraw Hill Ryerson 2007
1. Natural gas (methane) is burned in
furnaces to heat homes.
»CH4 + O2  CO2 + 2H2O + energy
2. An acetylene torch is used to weld
metals together.
»2C2H2 + 5O2  4CO2 + 2H2O + energy
3. Carbohydrates like glucose combine
with oxygen in our body to release
energy.
Acetylene torch
»C6H12O6 + 6O2  6CO2 + 6H2O + energy
See page 264
(c) McGraw Hill Ryerson 2007
MOVIE TO REVIEW: http://www.bcscience.com/bc10/pgs/videos_013_chemical_reactions.html
See page 265
(c) McGraw Hill Ryerson 2007