1. Teknologi Dan Rekayasa
Kompetensi Keahlian
Analisis Kimia

2. Techniques of Gravimetric Analysis

3. Objectives 4. To explain the gravimetric calculation
After this session, the students are expected to be able :
To explain the definition of gravimetric analysis
To explain the classification of methods used in gravimetric analysis
To explain the steps of techniques gravimetric analysis
4. To explain the gravimetric calculation
Teknologi dan Rekayasa

4. Preface
What is
gravimetric analysis?
Teknologi dan Rekayasa

5. Preface
Jobs to determinate the chemical composition of matter by weight
Teknologi dan Rekayasa

6. Quantitative analysis by weight with the steps :
Gravimetric Analysis
Quantitative analysis by weight with the steps :
Isolating
Weighing
Teknologi dan Rekayasa

7. The separation process
a. Precipitation methods
b. Volatilization or evolution
methods
c. Electro analytical
d. Extraction and
chromatographic methods.
Teknologi dan Rekayasa

8. Precipitation analysis
Steps of gravimetric analysis by precipitation method:
1. Weighing sample
2. Diluting sample into beaker glass
3. Precipitation process
4. Filtration
5. Washing precipitate
6. Drying precipitate
7. Weighing precipitate
8. Calculation of gravimetric analysis
Teknologi dan Rekayasa

9. The precipitate must be
1. insoluble
2. readily separated from the
solution by filtration, and
can be washed free of
soluble impurities.
3. convertible into a pure
substance of definite chemical
composition
Teknologi dan Rekayasa

10. Volatilization Heating method - Lost on ignition
- Humidity/volatile matter
- Ash
- TS/TDS
2. Chemical method
- CO2 liberating from carbonate
compound
CO3= + H+  CO2 + H2O
Teknologi dan Rekayasa

11. Gravimetric Calculation
The weight percent of constituent is equal to the weight of constituent divided by the sample weight and multiplied by 100
Teknologi dan Rekayasa

12. Gravimetric Calculation
Weight of substance x100 =percent by weight
Weight of sample
A general equation for gravimetric calculation is:
Weight of precipitate x gravimetric factor x 100 = % constituent
Teknologi dan Rekayasa

13. Gravimetric Calculation
For example, if a g sample of limestone is found to contain g of calcium, it has
x 100 = % calcium
1.0000
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14. Gravimetric factor
In most cases, however, the desired constituent is not weighed directly but is precipitated and weighed in some other compound
It is necessary to convert the weight to the weight in the desired form by
a gravimetric factor
Teknologi dan Rekayasa

15. Gravimetric factor
Gravimetric factor is the ratio of constituent (Ar) to compound (Mr)
For example, silver chloride is made up of silver and chloride. The ratio of silver to chloride is as Ag/AgCl
Since the atomic weight of Ag is 107.8
and that of chloride is 35.5
107.8/( ) =
This is called the gravimetric factor
Teknologi dan Rekayasa