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

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