We’ve recently updated our Chemistry A Level and GCSEs specification in recognition of IUPAC’s review of the definition of the mole. In January 2018, a new definition of the mole was recommended. In November 2018, the revised definition was approved, and it will subsequently come into force on 20 May 2019.
For more details on the new definition, see the announcement on the IUPAC website.
Our update to the specification adds additional guidance that clarifies that we will accept both the classical (carbon-12 based) and revised (Avogadro constant based) definitions of the mole in examinations.
If you have any questions, please contact the science subject team on 01223 553998 or at firstname.lastname@example.org.