Equations and Reaction Types

Key Terms

  • Element: Substance with the same type of atom (same number of protons).

  • Atom: Smallest particle of a chemical element (protons, neutrons, electrons).

  • Molecule: Two or more atoms bonded together (covalently).

  • Compound: Substances containing atoms of different elements.

  • Ion: Substance that has lost or gained an electron (charge).

    • Cations (positive ions).

    • Anions (negative ions).

  • Monatomic: Made up of one single atom.

  • Diatomic: Made up of two atoms.

  • Polyatomic: Made up of several atoms.

Chemical and Ionic Formulas

  • Balancing chemical equations.

  • Correct state symbols.

  • Correct arrow (reversible or irreversible).

  • Half and full ionic equations (with and without spectator ions).

Reactions of Acids

  • Four main lab acids:

    • Hydrochloric acid (HClHCl).

    • Sulfuric acid (H2SO4).

    • Nitric acid (HNO3HNO_3).

    • Phosphoric acid (H3PO4).

  • Acid + Metal -> Salt + Hydrogen gas.

    • Example: Magnesium + Hydrochloric acid -> Magnesium chloride + Hydrogen gas.

  • Acid + Metal Oxide/Insoluble Hydroxide -> Salt + Water.

    • Example: Copper + Sulfuric acid -> Copper sulfate + Water.

  • Acid + Alkali (soluble metal hydroxide) -> Salt + Water.

  • Acid + Metal Carbonate -> Salt + Water + Carbon Dioxide.

    • Example: Lithium carbonate + Hydrochloric acid -> Salt + Water + Carbon dioxide.

  • Acid + Hydrogen Carbonates -> Salt + Water + Carbon Dioxide.

    • NaHCO3 + HNO3 — > NaNO3 + H2O + CO2

Displacement Reactions

  • One element replaces another in a compound.

  • Can be redox reactions (oxidation and reduction).

  • Metals and aqueous solutions.

  • Halogens (reactivity series).

  • More reactive metal replaces less reactive metal.

  • Solid-state reactions (e.g., thermite reaction with aluminum and iron oxide) require high energy.

Precipitation Reactions

  • Formation of a solid.

  • Chemical tests:

    • CO2CO_2: White precipitate of calcium carbonate.

    • Sulfate ions: White precipitate of barium sulfate.

    • Halide ions: Precipitates of silver halides (white, cream, yellow).

    • Examples: Formation of calcium carbonate precipitate or lead iodide precipitate.