Write the steps in deducing the chemical formula of ferric phosphate.

Write the steps in deducing the chemical formula of calcium oxide.

Write the steps in deducing the chemical formula of aluminium hydroxide.

Explain how the element sodium is monovalent.

M is a bivalent metal. Write down the steps to find the chemical formulae of its compounds formed with the radicals, sulphate and phosphate.

Explain the need for a reference atom for atomic mass. Give some information about two reference atoms.

What is meant by Unified Atomic Mass?

Explain with examples what is meant by a 'mole' of a substance.

Write the name of the ${\mathrm{Na}}_2{\mathrm{SO}}_4$ compound and deduce its molecular mass.