STOICHIOMETRY
The branch of chemistry which deals with the quantitative relationship of the reactants and the products as given in the balanced chemical equation.
A statement that describes a chemical reaction in terms of symbols and chemical formulas is called a chemical equation.
Example:
C + O2 CO2
2H2+ O2 2H2O
Limitations of a chemical equation
The limitations of a chemical equation are as follows:
1. Chemical equation does not show the rate of the reaction.
2. It does not tell about the conditions necessary for the reaction.
3. The chemical equation can even be written to describe a chemical change that doesn’t occur.
Stoichiometric Amounts:
The amounts of the reactants or the products as given by the balanced chemical equation are called stoichiometric amounts.
2H2 + O2 2H2O
Stoichiometric amounts (i) 2moles 1mole 2moles
(ii) 4g 32g 36g
Assumptions To Perform Stoichiometric Calculations:
Following are the assumptions to perform stoichiometric calculation.
• All the reactants (in stoichiometric amounts) are completely converted into the products (Law of conservation of mass is obeyed).
• No side reaction occurs. (Law of definite proportions is obeyed).
• The reaction must be irreversible.
Stoichiometric Relations:
The following types of relationships can be studied with the help of a balanced chemical equation.
• Mass-mass relationship.
• Mass-mole relationship.
• Mass-volume relationship.
• Mole-mole relationship.