Introduction to chemical formulae

Intros
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Lessons
  1. What is a chemical symbol?
  2. What is a chemical formula? (Law of definite proportions).
  3. The composition of mixtures and compounds.
  4. Mistakes to avoid when using chemical formulae.
Examples
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Lessons
  1. Recall how to read molecular formulae of simple compounds
    Study the following chemical formulae:

    HCl, H2_2SO4_4 , HNO3_3 , H3_3PO4_4 , Ca3_3(PO4_4)2_2

    For each chemical formula, identify the chemical elements it shows and the number of atoms of each element in the compound.
  2. Apply your knowledge to write the chemical formulae of simple compounds and molecules.
    Write the chemical formulae for:
    1. Oxygen gas, a chemical molecule made of two oxygen atoms.
    2. Hydrogen gas, a chemical molecule made of two hydrogen atoms.
    3. Hydrochloric acid, a compound made of one atom of hydrogen and one atom of chlorine.
    4. Water, a compound made of two atoms of hydrogen and one atom of oxygen.
    5. Sodium Chloride, a compound made of one atom of sodium and one atom of chlorine.
    6. Potassium hydroxide, a compound of a potassium atom chemically combined with a hydroxide 'ion' which has the formula 'OH'