Gravimetric analysis is a type of quantitative chemical analysis in which the amount of a substance is determined by measuring its mass. It is one of the most accurate methods for determining the quantity of a specific component in a sample.
Key Points:
- Purpose: To find the quantity of a substance by converting it into a pure, stable, and weighable compound.
- How it Works:
- A specific reaction is carried out to form an insoluble precipitate containing the substance to be measured.
- The precipitate is filtered, washed, dried or ignited, and then weighed.
- Using stoichiometry, the mass of the original substance is calculated from the mass of the precipitate.
- Steps Involved:
- Precipitation of the substance.
- Filtration to separate the precipitate.
- Washing to remove impurities.
- Drying or ignition to constant weight.
- Weighing and calculation.
- Examples:
- Determining the amount of barium by precipitating it as barium sulfate (BaSO₄).
- Determining chloride ions by precipitating silver chloride (AgCl).
In short: Gravimetric analysis measures the mass of a product formed from a known chemical reaction to accurately calculate the amount of the substance present in a sample.