6.12 - Different types of formulae

Question 1

What are the two main ways to refer to organic compounds?

Answer 1

By formulae or by name

Question 2

What does a displayed formula do?

Answer 2

Shows every atom and every bond in a compound separately

Question 3

What does a structural formula do?

Answer 3

Shows what is attached to each carbon atom

Question 4

What does a skeletal formula do, and what does it look like?

Answer 4

Shows bonds between carbon atoms as lines, as well as anything that isn’t a hydrogen atom. It generally looks like a zig-zag

Question 5

What is the molecular formula of a compound?

Answer 5

The actual number of atoms of each element present in a compound

Question 6

What is an empirical formula?

Answer 6

The lowest whole number ratio of the atoms of each element present in a compound

Question 7

What are the molecular formula and empirical formula for ethene?

Answer 7

Molecular formula = C2H4

Empirical formula = CH2

Question 8

Can the molecular formula and empirical formula for a compound ever be the same?

Answer 8

Yes. This happens most commonly when there is only 1 atom of an element in the compound, as it means the ratio is already simplified

e.g. Chloroethane