lab 1

Question 1

analytical chem?

Answer 1

the study of:

• seperation
• identfication
• quantfication

Question 2

Qualitative analysis?

Answer 2

Identification of unknown compounds

(Cations and Anions)

Question 3

Quantitative analysis?

Answer 3

Determination of the amount of a certain component.

Question 4

What are Cations?

Answer 4

•Positive ions or metal ions (ex: Na+ )

Question 5

How will we identify Cations?

Answer 5

•Cations (metal ions or basic radicals) are classified into several groups on the basis of their behavior against some reagents (group reagents).

Question 6

how do we classify cations?

Answer 6

• Classification is based on whether a cation reacts with the group reagent by formation of precipitate or not.
• It can therefore be said that the classification of cations is based on the differences of the solubilities of their chlorides, sulphides, hydroxides and carbonates.

Question 7

group I reagent, ions, formulae of ppts. and distinguishing factors?

Answer 7

• cold dil. HCL
• Ag⁺, Pb⁺⁺
• AgCl, PbCl₂
• chlorides insoluable in cold dil. HCL

Question 8

**Why did HCl precipitate Ag+ but did not precipitate Cu++?

Answer 8

• This depends on the solubility product (Ksp) of the two salts
• CuCl₂ has a high Ksp while AgCl has a low Ksp

Question 9

what is k_sp?

Answer 9

The product of the concentration of ions in a saturated solution, at a given temperature.

K_sp= [Ag⁺][Cl^-]

Question 10

Summary of K_sp concept?

Answer 10

1. . In order to precipitate a slightly soluble electrolyte, the product of the ions must exceed the solubility product constant (for the given temperature).
2. . When the product is just reached, but not exceeded, the solution is saturated.
3. To dissolve a precipitate, the product of the concentrations of the ions must be kept below the solubility product constant of the precipitate.