n(a) science (chem) chp 13b preparation of salts
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NA Science (Chemistry) Chp 13b: Preparation of Salts (Notes)
Preparation of Salts Chapter 13b
Name: Class: Date:
What are Salts?
Salts consist of two parts: the acid part and the base part.
Salts are formed when:
i. acid + alkalis salt + water
ii. acid + metal carbonate salt + carbon dioxide + water
iii. acid + metal salt + hydrogen
acids base or alkali salt product
name formula name formula name formula
hydrochloric acid HCl sodium hydroxide NaOH sodium chloride NaCl
hydrochloric acid HCl magnesium oxide MgO magnesium chloride MgCl2
sulphuric acid H2SO4 potassium hydroxide KOH potassium sulphate K2SO4
sulphuric acid H2SO4 zinc oxide ZnO zinc sulphate ZnSO4
nitric acid HNO3 iron (II) oxide FeO iron (II) nitrate Fe(NO3)2
nitric acid HNO3 copper (II) oxide CuO copper (II) nitrate Cu(NO3)2
Hillgrove Secondary School P a g e | 1
NA Science (Chemistry) Chp 13b: Preparation of Salts (Notes)
Solubility of Salts
Different salts have different solubility.
soluble salts insoluble salts
carbonates sodium potassium ammonium
all others
chlorides all except lead, silver
nitrates all nitrates none
sulphateall except
lead, barium, calcium
From the table above, deduce the solubility of the following salts.
name of saltsolubility in water
(yes or no)
sodium sulphate Yes
copper (ii) nitrate Yes
zinc carbonate No
aluminium chloride Yes
barium sulphate No
silver chloride No
magnesium nitrate Yes
lead(II) sulphate No
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NA Science (Chemistry) Chp 13b: Preparation of Salts (Notes)
Preparation of Salts (Overview)
1. Preparation of insoluble salt
The above diagram shows the preparation of an insoluble salt, barium sulphate.
i. Starting from barium chloride, name the other reagent needed to produce barium sulphate.
sulphuric acid
ii. Suggest what is the solid at A. barium chloride
iii. What is the separation method used in B? filtration
iv. Why is distilled water used in C? to wash away excess acid from the barium sulphate sample
v. How do you obtain dry samples of barium sulphate after step C?
Press residue between sheets of filter paper
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AB C
barium chloride
sulphuric acid
NA Science (Chemistry) Chp 13b: Preparation of Salts (Notes)
2. Preparation of soluble salt
The steps below show the preparation of zinc sulphate using zinc and dilute sulphuric acid.
i. Zinc is added until excess zinc is seen. Why is excess zinc added?
to ensure that all the sulphuric has reacted
ii. What is this separation technique?
filtration
It is used to remove insoluble solid from a suspension.
The residue is zinc and the filtrate is zinc sulphate.
step iii step iv step v step vi
Suggest what is the method shown in steps iii to vi and why.
steps method reason
iii evaporation obtain a saturated zinc sulphate solution
iv crystallization form zinc sulphate crystals from the saturated solution
v filtration obtain zinc sulphate crystals from zinc sulphate solution
vi drying obtain dry zinc sulphate crystals
Hillgrove Secondary School P a g e | 4
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