2 Atoms, molecules and stoichiometryAS Level

2.1 Relative masses of atoms and molecules

2 of 2 objectives have lessons · 0 studied · 0 secure

Lessons

The unified atomic mass unitWhy chemists weigh atoms against carbon-12, the definition of the unified atomic mass unit, and what a relative isotopic mass tells you. 4 min, not started
Relative atomic mass: a weighted meanWhy chlorine is 35.5 when no chlorine atom weighs 35.5, how to define relative atomic mass, and how to calculate it from isotope abundances (forwards and backwards). 5 min, not started
Relative molecular mass and relative formula massHow to define and calculate Mr for molecules and relative formula mass for giant structures, and how to tell which term to use. 4 min, not started

Syllabus objectives

2 objectives

What Cambridge says you should be able to do, in our words. Codes are the topic number plus the objective’s position.

2.1.1

Define the unified atomic mass unit as one twelfth of the mass of a carbon-12 atom.

Taught in: The unified atomic mass unit · 4 questions

2.1.2

Define relative atomic mass, Ar, relative isotopic mass, relative molecular mass, Mr, and relative formula mass in terms of the unified atomic mass unit.

Taught in: Relative molecular mass and relative formula mass, Relative atomic mass: a weighted mean, The unified atomic mass unit · 16 questions