Chemical Formulae

CHEMICAL FORMULAE & EQUATIONS 3.5 Chemical Formulae

3.5 Chemical Formulae

At the end of this lesson, you should be able to: 1. State the meaning of chemical formula. 2. State the meaning of empirical formula. 3. State the meaning of molecular formula. 4. Determine empirical & molecular formula of substances. 5. Compare and contrast empirical formula with molecular formula. 6. Solve numerical problems involving empirical & molecular formula.

3.5 Chemical Formulae

Chemical Formula Molecular Formula

Empirical Formula Calculation & Determination

Numerical Problems

3.5 Chemical Formulae

Chemical Formula Representation of a chemical substance using letters for atoms and subscript numbers to show the numbers of each type of atoms that are present in the substance.

CuSO4 Copper (II) Sulphate

3.5 Chemical Formulae

Information from chemical formula

All the elements present in the compound

Calculate Mr or Relative Formula Mass Number of atoms of each element

3.5 Chemical Formulae

Empirical Formula Elements Mass (g) or % of element No. of moles of atoms Ratio of moles Simplest ratio of moles

Formula that shows the simplest whole number ratio of atoms of each element in the compound X

Y

3.5 Chemical Formulae

Formula that shows the actual number of atoms of each element that are present in the compound

Molecular Formula

Molecular = ( Empirical Formula )n Formula