Types of Chemical Reactions

1. Types ofChemical Reactions

2. 1. Synthesis Reactions • A synthesis reaction occurs when two or more reactants combine to form just one product. • The general equation for a synthesis reaction is: A + B  AB • What to look for: If there is only one product – you can bet it’s a synthesis. Examples of Synthesis Reactions • 2H2 + O2 2H2O • CO2 + H2O  H2CO3 • HCl + NH3  NH4Cl

3. 2. Decomposition Reactions • A decomposition reaction occurs when a single reactant splits into smaller compounds or elements. • The general equation for a decomposition reaction is: AB  A + B • What to look for: If there is only one reactant – you can bet it is a decomposition. Examples Decomposition Reactions • NH4NO3 N2O + 2H2O • 2NI3  N2 + 3I2 • 2H2O  2H2 + O2

4. 3. Single Displacement Reactions • A single displacement reaction occurs when a single element takes the place of one of the elements in a compound. • The general reaction for a single displacement reaction is: AB + Z  ZB + A • Metals will displace other metals and nonmetals will displace other nonmetals. • What to look for: Look for the single element to break up a couple and take the place of someone in that couple. Examples of Single Displacement Reactions • Mg + 2AgNO3 Mg(NO3)2 + 2Ag • Br2 + CaI2 CaBr2 + I2 • Ca + FeCl2 CaCl2 + Fe

5. 4. Double Displacement Reactions • A double displacement reaction occurs when two compounds switch their metals (or nonmetals). • The general equation for a double displacement reaction is: AB + YZ  AZ + YB • Again, metals switch with metals and vice-versa. • What to look for: It is like switching partners at a dance. Two couples enter, switch partners, and two couples exit. Examples of Double Displacement Reactions • CaCl2 + MgO  CaO + MgCl2 • Pb(NO3)2 + 2KI  PbI2 + 2KNO3 • HCl + NAOH  NaCl + H2O

6. 5. Combustion Reaction • A combustion reaction is a special type of reaction in which a substance (called a fuel) reacts very rapidly with oxygen gas (O2) to produce carbon dioxide (CO2) and water (H2O). • Combustion reactions release a lot of energy as they proceed. • The general equation for a combustion reaction is: Fuel + O2 CO2 + H2O • What to look for: Oxygen and a “fuel” as the reactants with carbon dioxide and water being the products. Examples of Combustion Reactions • CH4 + 2O2 CO2 + 2H2O • C3H8 + 5O2  3CO2 + 4H2O

7. Incomplete Combustion • Incomplete combustion occurs when there is not enough oxygen available for the fuel to burn cleanly. • There are four products instead of two – carbon monoxide (CO) and carbon (C) join water (H2O) and carbon dioxide (CO2). • Overall… Fuel + O2 CO2 + H2O + CO+ C

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