Empirical formula calculations: using moles
I can determine the empirical formulae of simple compounds using reactant masses or percentage composition.
Empirical formula calculations: using moles
I can determine the empirical formulae of simple compounds using reactant masses or percentage composition.
These resources will be removed by end of Summer Term 2025.
Lesson details
Key learning points
- Empirical formula is the simplest whole number ratio of atoms of each element in a compound.
- Using the masses of elements reacted together, or their percentage compositions, calculate the empirical formula.
- Knowing the relative formula mass of a substance, and its empirical formula, calculate the molecular formula.
- Know that we are using moles, and molar ratios to calculate formulae
Keywords
Empirical formula - A substance's empirical formula shows the simplest whole number ratio of atoms of each element in a compound.
Relative formula mass - The relative formula mass of a substance is the sum of the relative atomic masses of all the atoms in a formula.
Molecular formula - A substance's molecular formula shows the actual number of atoms of each element in a molecule of a compound.
Mole - A mole of something is 6.02 × 10²³ of it. The mass of a mole of a substance is its relative mass expressed in grams.
Common misconception
Pupils easily confuse empirical and molecular formula.
Provide multiple examples of formula and challenge pupils to distinguish them as molecular or empirical formula; if the former, push pupils to suggest the molecule's empirical formula.
To help you plan your year 10 chemistry lesson on: Empirical formula calculations: using moles, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your year 10 chemistry lesson on: Empirical formula calculations: using moles, download all teaching resources for free and adapt to suit your pupils' needs.
The starter quiz will activate and check your pupils' prior knowledge, with versions available both with and without answers in PDF format.
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Explore more key stage 4 chemistry lessons from the Calculations involving masses unit, dive into the full secondary chemistry curriculum, or learn more about lesson planning.
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