CHEMICAL FORMULAE & CHEMICAL FORMULAE & EQUATIONSEQUATIONS

3.5 Chemical Formulae3.5 Chemical Formulae

At the end of this lesson, you should be able to:

3.5 Chemical Formulae

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

Empirical Formula

Molecular Formula

Calculation &

Determination

Chemical Formula

Numerical Problems

Copper (II) Sulphate

3.5 Chemical Formulae

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

Chemical Formula

3.5 Chemical Formulae

Information Information from from

chemical chemical formula formula

All the elements

present in the compound

Number of atoms of

each element

Calculate Mr or Relative

Formula Mass

3.5 Chemical Formulae

Formula that shows the simplest whole

number ratio of atoms of each element in the

compound

Empirical Formula

Elements X Y

Mass (g) or % of element

No. of moles of atoms

Ratio of moles

Simplest ratio of moles

3.5 Chemical Formulae

Molecular Formula

Formula that shows the actual number of

atoms of each element that are present in the

compound

Molecular Formula

= ( Empirical Formula )n