chem reactions

Synthesis

• A + X → AX
• A and X can be elements or simple compounds
• AX is a compound
• element + oxygen → oxide of element
• metals + sulfur → sulfides
• nonmetals + oxygen → oxides
• oxides of active metals + water → metal hydroxides

Decomposition

• AX → A + X
• electrolysis - decomposition of water using electricity
• exceptions
• metal carbonate → metal oxide + carbon dioxide
• metal hydroxide → metal oxide + water vapor
• metal chlorate → metal chloride + oxygen gas

Single Replacement

• A + BX → AX + B where A+B are metals
• Y + BX → BY + X where Y+X are nonmetals
• reactivity
• group 1A increases ↓
• halogens decreases ↓
• most active metals + water → metal hydroxide + hydrogen gas
• less active metals + steam → metal oxide + hydrogen gas
• more reactive metals + some acids

Double Displacement

• AX + BY → AY + BX
• one compound produced:
• precipitate
• insoluble gas
• molecular compound (usually water)
• other compound usually aqueous

Combustion

• Cx + Hy + O2 → CO2 + H2O

Identification

1. only one reactant? → decomposition
2. reactants two elements / simple compounds? → synthesis
3. reactants oxygen + hydrocarbon? → combustion
4. reactants element + compound (not hydrocarbon) → single
5. reactants two compounds composed of ions? → double