Mass in a chemical reaction: using moles (RAM 1 d.p.)
I can interpret a balanced symbol equation to predict the mass of either a reactant or a product.
Mass in a chemical reaction: using moles (RAM 1 d.p.)
I can interpret a balanced symbol equation to predict the mass of either a reactant or a product.
These resources will be removed by end of Summer Term 2025.
Lesson details
Key learning points
- Stoichiometry means ‘measuring elements’, from the Greek 'stoikhein' – meaning element and 'metron' – to measure.
- Chemical equations should be interpreted in terms of moles (i.e. 1 mole of this reacts with 2 moles of that).
- The mass of each reactant that does react can be worked out from the relative formula masses in the chemical equation.
- In a chemical reaction, the atoms in reactants are rearranged and are the same atoms that are in the products.
- The mass of products in a chemical reaction is equal to the mass of the reactants.
Keywords
Stoichiometry - Stoichiometry refers to the molar ratio of the reactants and products in a chemical reaction.
Relative formula mass - The relative formula mass (RFM or Mᵣ) of a substance is the sum of the relative atomic masses of all the atoms in its formula.
Mole - 1 mole of a substance is 6.02 × 10²³ particles of it. The mass of a mole of a substance is its relative mass in grams.
Common misconception
Pupils struggle to recall the order of steps required to mathematically process the available information in order to answer the question.
Colour-coding the steps can help pupils remember how many steps are involved. Much practice and perseverance is needed to create and maintain the memory pathway of the mathematical processing.
Equipment
Licence
This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).
Lesson video
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