Science & Technology in Action

9th Edition

How Chemistry Serves Society


Many industries are founded on chemistry and this lesson describes how chemistry underpins many processes. The concept of the chemical formula is examined and the terms ‘chemical formula’ and ‘structural formula’ are differentiated.
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Contains the full lesson along with a supporting toolkit, including teachers’ notes.

Lesson excerpt

The importance of chemistry
Chemistry is the foundation of many industries. Almost everything we use in our daily lives is made from the products of the chemical industry: cars, electronic devices, paints, perfumes, disinfectants, pharmaceuticals and much of our clothes. Few metals are found free in nature; most occur as oxides, sulfides or other compounds which must be chemically decomposed to extract the metal. So many chemicals are produced from petroleum that the term ‘petrochemicals’ is used to describe them; they include fuels (liquid and gas), oils, lubricants, solvents, plastics, fibres, dyes, inks and many more.

This lesson reviews many aspects of chemistry and shows how they are applied in industry.

Chemical formulae
A chemical formula is a compact way to describe the chemical composition of a substance. It tells what elements the substance contains and the number of atoms of each of these elements in one molecule of the substance. A chemical formula does not usually describe how the atoms are bonded but a structural formula does. Two different substances could have the same chemical formula but would have different structural formulae. For example C2H6O could have the following structural formulae:

CH3-O-CH3 (methoxymethane) or C2H5OH (ethanol).

These two substances have different functional groups and are referred to as functional isomers. Structural isomers on the other hand have the same functional groups but still have different structures; e.g. propan-1-ol and propan-2-ol (CH3.CH2.CH2OH and CH3.CHOH.CH3)

To read the full lesson, download the pdf above.

True or False?

  1. A molecular formula indicates what elements the molecule contains and in what proportion. true
  2. A structural formula indicates which atoms are bonded within a molecule. true
  3. Carbohydrates are composed of hydrogen and oxygen only. false
  4. Propane (C3H8) has two structural isomers. false
  5. Water is 12.5% hydrogen and 87.5% oxygen. false
  6. Stoichiometry is the study of relative amounts of elements that react or that combine to form to a new substance. true
  7. An endothermic reaction is one that gives out energy. false
  8. The majority of manufactured goods are made from the products of the chemical industry.
  9. Hydrocarbons in which all the bonds are single bonds are called alkenes. false

Glossary of terms

chemical equation
chemical formula