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

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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

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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 togetherExample: 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!

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Combustion Reaction

• Organic compounds react with oxygen to produce carbon dioxide and water

• Ex) CH4 + 2O2 CO2 + 2H20• Ex) C6H12O6 + 6O2 6CO2 + 6H20

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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