BRAINCAKEQuantitative chemistry
Revision notes for Quantitative chemistry in AQA Combined Science: Trilogy (8464). Every lesson in BrainCake comes with R.E.C.I.P.E. recall steps, a quick check and spaced reviews.
- Conservation of mass and balanced chemical equationsThe law of conservation of mass says that no atoms are lost or made during a chemical reaction.
- Relative formula massThe relative formula mass (Mr) of a compound is the sum of the relative atomic masses (Ar) of all the atoms in the formula, in the numbers shown.
- Mass changes when a reactant or product is a gasSome reactions seem to break the law of conservation of mass, but the apparent change in mass can usually be explained because a reactant or product…
- Chemical measurementsWhenever a measurement is made there is always some uncertainty about the result.
- Moles (HT only)Chemists count particles in a unit called the mole, symbol mol.
- Amounts of substances in equations (HT only)A balanced symbol equation can be read in terms of moles.
- Using moles to balance equations (HT only)The balancing numbers in an equation are the ratio of the moles of each substance.
- Limiting reactants (HT only)In many reactions two reactants are mixed and one is used in excess.
- Concentration of solutionsMany reactions take place in solution.