Conservation of mass
What Conservation of mass means in Combined Science GCSE, as defined for AQA.
Definitions of Conservation of mass
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Reference: AQA
Law meaning the number of atoms of each element is the same before and after reaction, so the mole ratio must be a simple whole-number ratio.
The calculated masses must always be consistent with this law, meaning the total reactant mass equals the total product mass.
No atoms are lost or made during a chemical reaction, so the mass of the products equals the mass of the reactants.
Atoms are conserved in a chemical reaction, so the total mass of atoms on each side is unchanged.
Topics that use Conservation of mass
- Amounts of substances in equations (HT only) (AQA GCSE)
- Conservation of mass and balanced chemical equations (AQA GCSE)
- Relative formula mass (AQA GCSE)
- Using moles to balance equations (HT only) (AQA GCSE)
Related terms
- Relative formula mass
- Balanced symbol equation
- Balancing numbers
- Mole ratio
- Subscripts
- Balanced symbol equations
- Balancing
- Closed systems
Using Conservation of mass in the exam
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