Gravimetric Method Flashcards
This consists of isolating from the sample the constituent to be determined in its pure state and weighing it accurately.
Gravimetric analysis
Isolation may be done by:
❖ precipitating the sought substance in an insoluble form
❖ electrolysis
❖ converting the substance to a gas which is absorbed in a suitable reagent.
most common in isolation
precipitating the sought substance in an insoluble form
electrolysis is the?
separation of ions
Precipitation characteristics
- low solubility
- large in particle
- easy filtered
- pure and stable
- Solubility Product Principle
The ionic product exceeds the ________________, precipitation will occur
solubility product constant (KSP)
- The common ion effect
If there is an excess of one ion over the other, the solubility of the precipitate will __________
decrease
- Law of mass action
The rate of the reaction is ______________ to the product of the molecular concentrations of the reacting substance
directly proportional
Steps of Gravimetric Method by Precipitation
- Dissolve sample
- Add ppt’ing reagent
- Filter
- Dry
- Weigh
