5 categories of chem. rxn.

1. Synthesis

2. Decomposition

3. Single replacement

4. Double replacement

5. Combustion

1. Synthesis

Two or more substances put together

A + B ABGeneral

Specific Example

2Na + Cl2 2NaCl

2. Decomposition

Compound breaks down into 2 (or more) substances

AB A + BGeneral

Specific Example

H2O2 H2O + O22 2

• Hydrogen peroxide decomposes into water & oxygen gas

3. Single-replacement

One element replaces another in a compound

AB + C CB + AGeneral

MgCl2 + 2 Li 2LiCl + Mg

• Li takes place of Mg

3CuSO4+2Al Al2(SO4)3+ 3Cu

• Al takes the place of Cu

Specific Example

4. Double replacement

The positive portions ( + ions) are exchanged

General

AX + BY AY + BX

Specific Example

AgNO3+NaBr AgBr +NaNO3

• Ag+ & Na+ exchange places

5. CombustionSubstance combines w/ oxygen rapidly - forms one or more oxides

Substance A + O2

Substance oxide + energy

• releases energy

Specific Example

2 C2H2 + 5 O2 4 CO2 + 2 H2O + energy

• Acteylene combines w/ oxygen & produces carbon dioxide & water & releases energy

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