Preamble

Many of the materials balance problems that arise in metal extraction processes can be solved easily with either.

a) Knowledge of atomic/molecular weights of reactants and products appearing in a balanced chemical reaction, or

b) From mass of compound contained in a given volume of gas.

Stoichiometry can be used to develop the above relationship.

Basics of stoichiometry 

• Atomic or molecular mass of an element and compound. Molecular weight of a compound is theaddition of molecular weight (Atomic weight) of elements comprising the compound. For  example

Molecular Weight of ZnS = Molecular Weight of Zn + Molecular Weight of S

Similarly molecular weight of

• The chemical equation : law of conservation of mass

For any chemical reaction, the number of atoms of elements in the product = No. of atoms of that elements in the reactants.