6.1 Types of Chemical
Reactions
6 Types of Reactions
•
•
•
•
•
•
Synthesis (Combination) (3)
Decomposition (3)
Single replacement (4)
Double Replacement (4)
Neutralization (acid-base) (4)
Combustion (4)
Synthesis Reactions
+

• 2 or more reactants combine to
form a single product
• Element + Element  Compound
• A + B  AB
• Ex) 2Na + Cl2  2NaCl
Synthesis Reactions
-Do not write down• Make sure to consider the ion
charge of both reactants before
forming the product
Mg2+ O2- both have 2- ion charge
so they combine as Mg O
• Now balance
• Ex) 2Mg + O2  2MgO
Practice
• Pg 259 #1/2 a,c,e
• Check answers- Pg 592
Decomposition Reactions

+
• Breaking down a compound into smaller
compounds or elements
• Reverse of synthesis
• Compound  Element + Element
• AB  A + B
• 2NaCl  2Na + Cl2
Decomposition Reactions
• Both parts of the compound go
back to their element form (no
ion charge)
• If they are diatomic, make sure
to write the 2
Practice
• Pg 260 #1/2 a,c,
• Check answers- Pg 592
Single Replacement Reactions
+

+
• An element and a compound react to
produce another element and
compound
• Element + Compound  Element + Compound
• A + BC  B + AC
• Metals and non-metals go together
Example: 2Al + 3CuCl2 3Cu +2AlCl3
Practice
• Pg 261 #1/2 a,c,
• Check answers- Pg 592
Double Replacement Reactions
• Two ionic solutions react to form two
other ionic solutions
• Ionic solution + Ionic solution  Ionic solution +
Ionic solid
• AB(aq) + CD(aq)  AD(aq) + CB(s)
• Ex) Pb(NO3)2 + 2NaI  PbI2 + 2NaNO3
Practice
• Pg 262 #1/2 a,c,
• Check answers- Pg 592
Neutralization Reaction
+

+
• Been done… check your notes!
Combustion Reaction
+

+
• Organic compounds react with oxygen to
produce carbon dioxide and water
• Ex) CH4 + 2O2  CO2 + 2H20
• Ex) C6H12O6 + 6O2  6CO2 + 6H20
Practice
• Pg 264 #1/2 a,c
• Check answers- Pg 592
• Now try the summary problems
Pg 265 #1-7
• Solutions on how to do them are
on the following page
Reaction Rates
• How fast a reaction occurs
• Can be fast or slow
Temperature
• Increase temp = increase rxn
rate
• Decrease temp = decrease rxn
rate
• Warmer = molecules move
faster = more collisions
Concentration
• Increased conc = increased rxn
rate
• Decreased conc = decreased
rxn rate
• More molecules = faster rxn
Surface Area
• Increase SA = increase rxn rate
• Decrease SA = decrease rxn
rate
• What burns faster: kindling or a
large log?
Catalyst
• Speeds up a rxn but is not used
up
• Lower energy needed for rxn to
start
• Eg: enzymes in your body
• Eg: catalytic converter in cars