Salt Preperation

Question 1

How can ypu derive which method to use to prepare a salt?

Answer 1

Question 2

What salt method preperation is used to prepare insoluble salt?

Answer 2

precipitation

Question 3

What salt method preperation is used to prepare soluble salt?

Answer 3

• g1 - titration
• all others - metal carbonate + acid OR metal oxide + acid

Question 4

What salt compounds are soluble?

Answer 4

• g1 compounds
• nitrate compounds
• halide compunds except those containing Ag+ and Pb2+
• sulfate compounds except those containing Sr+, Ba2+, Ca2+, Pb2+

Question 5

What salt compounds are insoluble?

Answer 5

• hydroxides compunds
• carbonate compunds
• oxide compounds (however, g1 react with them)

Question 6

what is the method to prepare a soluble salt that does not contain g1?

Answer 6

metal carbonate + acid OR metal oxide + acid
* add acid to a beaker and heatusing a bunsen flame
* add excess insoluble metal carbonate or metal oxide to acid (until base stps disappearing and a suspension of the base forms in the acid).
* filter mixture to remove excess solid
* heat solution to evaporate water
* leave the mixture to form salt crystals

Question 7

what is the method to prepare a soluble salt containing g1?

Answer 7

• use a pipette to measure ____cm^3 of the unkown (base) substance.
• add 2 drops of indicator (methyl orange or thymolphthaelein indicator) to the base
• fill burret with known (acid) substance and record initial substance.
• slowly add the acid into the beaker until change in color is observed.
• repeate the previous steps (1-4) without adding the indicator
• transfer solution to evaporating basin and ecvaporate 3/4 of the water
• leave salt crystals to crystalize

Question 8

What does the pipette measure?

Answer 8

The unkown chemical (conc.)

Question 9

What does the burret measure?

Answer 9

the known (conc.) chemical.

Question 10

why do we leave some water when evaporating?

Answer 10

• To make sure salt crystals are hydrated
• So that large salt crystals are formed
• To avoid salt decomposing

Question 11

what is the method to prepare an insoluble salt?

Answer 11

1. Dissolve soluble salts in water and mix together using a stirring rod in a beaker
2. Filter to remove precipitate from mixture
3. Wash the residue with distilled water to remove traces of other solutions
4. Leave in an oven to dry

Question 12

What are the impurities in the solution when making salts with metal carbonates or metal oxides and acids?

Answer 12

• water
• soluble impurities/reactants