chpt 8 salts

Question 1

What are the methods to prepare salts ?

Answer 1

1. adding excess solid reactant (reactive metal, base, carbonate)
2. titration
3. precipitation

Question 2

Describe process and conditions for adding excess to. be used.

Answer 2

1. prep most soluble salts EXCEPT group 1 and ammonium salts
2. excess reactive metal, carbonate and base
3. add excess____ into acid (sulfuric acid) and stir
4. filter mixture to filter out excess as residue
5. heat to saturation
6. cool for crystals to form
7. wash with little cold distilled water
8. dry btwn 2 pieces of filter paper

Question 3

Describe process and conditions for titration.

Answer 3

1. prep soluble grp 1 and ammonium salts (what adding excess does not prep)
2. acid plus soluble base / carbonate
3. pipette aqueous sodium hydroxide into conical flash
4. add 2 drops of methyl orange (universal indicator)
5. add dilute nitric acid from burette, slowly with stirring, until indicator changes colour
6. record amt of dilute nitric acid used
7. heat to saturation, filter for crystals, wash and dry

Question 4

Describe process and conditions for precipitation.

Answer 4

1. prep insoluble salts (precipitate, its in the name)
2. to reactants used must be in aq form
3. aq solution + aq solution -> insoluble salt + aq solution
4. mix fixed volume of barium nitrate with excess sodium sulfate together and stir
5. insoluble barium sulfate formed as insoluble salt, sodium nitrate as aq solution
6. filter to obtain precipitate as residue, wash and dry

Question 5

Name the insoluble silver compounds.

Answer 5

1. agcl
2. agi (silver iodide)
3. agbr (silver bromide)

Question 6

Name the insoluble lead compounds.

Answer 6

1. pbcl
2. pbso4
3. pbi
4. pbbr

Question 7

Solubility of carbonates, oxides and hydroxides ?

Answer 7

carbonate -insoluble except for grp 1and (nh4)2co3
oxides - insoluble except for grp 1 and cao is sparingly soluble
hydroxides - insoluble except from grp 1 ca(oh)2 is sparingly soluble