Preparation Of Salts - Chemistry Worksheet Page 3
ADVERTISEMENT
1
2
3
4CHEMISTRY Class Notes
Preparation of Salts
c) Filter off the excess copper(II) oxide (insoluble).
Reason: To ensure that the unreacted copper(II) oxide will not contaminate the salt
formed.
d) Heat the filtrate to saturate the copper sulfate salt solution. Do not heat to dryness.
Reason: By heating to dryness, the salt loses its water of crystallization and crystals will
not form.
e) When filtrate is saturated, let it cool and crystallize.
f) Wash the copper sulfate crystals with distilled water dry between pieces of filter paper.
4. Acid + Insoluble Carbonate
(to prepare soluble salts)
a) Starting materials for making magnesium chloride can be: magnesium carbonate and
hydrochloric acid.
Word equation: magnesium carbonate + hydrochloric acid à carbon dioxide + water +
magnesium chloride
(s) + 2HCl (aq) à CO
Chemical equation: MgCO
(g) + H
O (l) + MgCl
(aq)
3
2
2
2
b) Add excess magnesium carbonate to hydrochloric acid until there is no more reaction.
Reason: To ensure a complete reaction and all hydrochloric acid has been used up, so
that it will not contaminate the desired solution.
c) Filter off the excess magnesium carbonate (insoluble).
Reason: To ensure that the unreacted magnesium carbonate will not contaminate the
salt formed.
d) Heat the filtrate to saturate the magnesium chloride salt solution. Do not heat to
dryness.
Reason: By heating to dryness, the salt loses its water of crystallization and crystals will
not form.
e) When filtrate is saturated, let it cool and crystallize.
f) Wash the magnesium chloride crystals with distilled water dry between pieces of filter
paper.
5. Titration (acid with alkali or soluble carbonate solution)
(to prepare soluble salts)
· Salt to prepare is a soluble salt & both reagents are also soluble (aqueous solutions).
· Useful for preparing potassium, sodium and ammonium salts.
a) Starting materials for making sodium nitrate: sodium hydroxide and nitric acid.
Word equation: sodium hydroxide + nitric acid à sodium nitrate + water
(aq) à NaNO
Chemical equation: NaOH (aq) + HNO
(aq) + H
O (l)
3
3
2
b) Run a titration of the two reagents. One reagent will be in conical flask and the other
will be in the burette, using an indicator.
c) Once the end point is reached, the indicator will change colour, stop the titration and
record down the readings.
3
ADVERTISEMENT
0 votes
Related Articles
Related forms
Related Categories
Parent category: Education