• The?molecular?formula?is the formula that shows the?number?and?type?of each atom in a molecule
  • E.g. the molecular formula of ethanoic acid is C₂H₄O₂
• The?empirical?formula?is the simplest whole number ratio of the atoms of each element present in one molecule or formula unit of the compound
  • E.g. the empirical formula of ethanoic acid is CH₂O
• Organic molecules?often have?different?empirical and molecular formulae
• The formula of an?ionic?compound?is always an?empirical formula

Empirical formula

• The?empirical formula?is the?simplest whole number ratio?of the atoms of each element present in one molecule or formula unit of the compound
• It is calculated from a knowledge of the masses of each element in a sample of the compound
• It can also be deduced from data that give the?percentage composition by mass?of the elements in a compound

Answer:

Answer:

Molecular formula

• The?molecular formula?gives the actual numbers of each element present in the formula of the compound
• The molecular formula can be found by dividing the?relative?molecular massby the?relative mass?of the?empirical formula?and finding the multiple that links the empirical formula to the molecular formula
• Multiply?the empirical formula by this number to find the molecular formula

Answer:

Step 1:?Calculate the relative mass of empirical formula

Relative empirical mass = (C x 4) + (H x 10) + (S x 1)

Relative empirical mass = (12.01 x 4) + (1.01 x 10) + (32.07 x 1)

Relative formula mass = 90.21

Step 2:?Divide relative molecular mass of?X?by relative mass of empirical formula

The multiple between X and the empirical formula = 180.42/90.21 = 2

Step 3:?Multiply the empirical formula by 2

2 x C₄H₁₀S ? ?=? ? C₈H₂₀S₂

The molecular formula of?X?is?C₈H₂₀S₂