201 Chemistry/2.3

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Quantative chemistry is the study of 'how much'.

This unit is designed to prepare you for NCEA level 2 Achievement standard 90763: Solve simple quantitative chemical problems.

Before we start we need to remind ourselves of some definitions.

Scientific notation or standard form:

Significant figures:

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By the end of this unit you should be able to:
  • Calculate the molar masses of molecules from given molar masses of atoms and formulae.
  • Calculate mole ratios from given molar masses of atoms and their formulae.
  • Carry out calculations using the formulae: [math]n = \frac{m}{M}[/math] and [math] n = v \times c[/math]
  • Calculate the percentage composition of a compound
  • Determine the empirical and molecular formula of a compound.
  • Calculate the number of water molecules in the formula of a hydrated salt.

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It is useful to be able to write balanced equations