CAIE A Level Chemistry 9701 · Atoms, molecules and stoichiometry
The relative atomic mass of hydrogen is 1.0 and that of oxygen is 16.0, based on the carbon-12 scale. With reference to the definition of the unified atomic mass unit, explain the meanings of relative atomic mass and relative molecular mass, and distinguish between relative molecular mass and relative formula mass.
4 marks, so the mark scheme is looking for about 4 separate creditworthy points. Making the same point twice in different words earns it once.
Explain means: Give the reasons or the mechanism: why or how something happens. Link each point to the next with because, so or which means. A list of facts with no links usually loses the reasoning marks.
Written by Markquill to follow the Cambridge International syllabus. Markquill is independent and is not affiliated with or endorsed by Cambridge International.