Gravimetric Method

Question 1

This consists of isolating from the sample the constituent to be determined in its pure state and weighing it accurately.

Answer 1

Gravimetric analysis

Question 2

Isolation may be done by:

Answer 2

❖ precipitating the sought substance in an insoluble form
❖ electrolysis
❖ converting the substance to a gas which is absorbed in a suitable reagent.

Question 3

most common in isolation

Answer 3

precipitating the sought substance in an insoluble form

Question 4

electrolysis is the?

Answer 4

separation of ions

Question 5

Precipitation characteristics

Answer 5

• low solubility
• large in particle
• easy filtered
• pure and stable

Question 6

1. Solubility Product Principle

The ionic product exceeds the ________________, precipitation will occur

Answer 6

solubility product constant (KSP)

Question 7

2. The common ion effect

If there is an excess of one ion over the other, the solubility of the precipitate will __________

Answer 7

decrease

Question 8

3. Law of mass action

The rate of the reaction is ______________ to the product of the molecular concentrations of the reacting substance

Answer 8

directly proportional

Question 9

Steps of Gravimetric Method by Precipitation

Answer 9

• Dissolve sample
• Add ppt’ing reagent
• Filter
• Dry
• Weigh