Sherpa

Existing user?

Combined Science: Chemistry

GCSE · Edexcel · higher

QuestionsFlashcards

Group 1
- Group 1 (Alkali Metals)
  5
- Group 1: Reactivity & Electronic Configurations
  3
Group 7
Group 0

Empirical Formulae Flashcards

All 5 cards in this deck

What is an empirical formula?: The formula showing the simplest whole number ratio of atoms of each element in a compound.
What is a molecular formula?: The formula showing the actual number of atoms of each element in one molecule of the substance.
How do you deduce the empirical formula from a molecular formula? e.g. ethene, $\mathrm{C_2H_4}$: Divide all the subscripts by their highest common factor.

e.g. $\mathrm{C_2H_4}$ → $\mathrm{CH_2}$
How is the molecular formula related to the empirical formula and the $M_r$ ?: Multiply every number in the empirical formula by $M_r$ ÷ (relative mass of the empirical formula).
True or false? An ionic compound such as sodium chloride is normally written as its empirical formula.: True. Ionic compounds have giant lattices, so the formula gives the simplest ratio of ions.