Gravimetric Analysis: Principle and Steps

Principle

• Gravimetric analysis is a quantitative method that determines the amount of an analyte based on its mass.

• The analyte is isolated, typically as a precipitate, which is then weighed to calculate the analyte's concentration.

Steps in Gravimetric Analysis

1) Sample preparation

• Weigh a known amount of the sample and dissolve it in a suitable solvent (e.g., distilled water).

• Filter to remove impurities if necessary.

2) Precipitation

• Add a precipitating agent that reacts selectively with the analyte to form an insoluble precipitate.

3) Digestion

• Allow the precipitate to settle, often by heating or standing, to improve purity and particle size.

4) Filtration

• Filter the precipitate to separate it from the solution using appropriate filter paper.

5) Washing and drying

• Wash the precipitate to remove impurities, then dry it in an oven or desiccator to remove moisture.

6) Weighing

• Weigh the dried precipitate using an analytical balance.

7) Calculation

• Use the mass of the precipitate and the stoichiometry of the reaction to determine the analyte's concentration.

This concise process ensures the accurate determination of an analyte based on its mass.