These notes will help you to understand and apply

• Relative atomic mass, Ar
• Relative molecular mass, Mr, and calculate relative molecular mass.
• Mole in terms of the Avogadro constant
• Calculate percentage mass of an element in a compound.
• Calculate empirical and molecular formulae.
• Calculate stoichiometric reacting masses and volumes of gases
• Concept of solution concentration to process the results of volumetric experiments and to solve simple problems.
• Calculate % yield and % purity.

These O levels Biology notes are suitable for students in Sec 3/4 taking Pure or Combined Chemistry.