Revision on acid base and salt = with answers
description
Transcript of Revision on acid base and salt = with answers
Chemistry revision form 5 - 2011
Topic
acid base and salt
Chlorides salts
Sulphates salts
soluble salts
All soluble except
All soluble except
Insoluble salts
•a) Soluble and Insoluble salts
Nitrate salts
carbonate salts
soluble salts
All soluble
Insoluble salts
All insoluble except
•a) Soluble and Insoluble salts
SALT PREPARATION METHODS
SOLUBLE SALTS ( must start with )
TITRATION METHOD( reaction between and )
SOLID
AND HOT ACID METHODFor soluble salts of
salts
For all soluble salts
SALT PREPARATION METHODS
INSOLUBLE SALT( the reactants must be in
form)
METHOD
Excess copper (II) oxide powder
Acid xxxxxxxxxxxx
Heat
State the colour of •copper (II) oxide powder
•copper(II) sulphate solution
Based on Diagram, name the acid used to prepare copper (II) sulphate.
Write the chemical equation for the preparation of copper (II) sulphate.
State the reason why copper (II) oxide powder is added until in excess.
Describe how to obtain pure crystals from solution of copper (II) sulphate in the beaker above.
0.1 mol of copper (II) sulphate is produced from the reaction between acid and excess copper (II) oxide.Calculate the mass of copper (II) sulphate formed.
Describe chemical tests to verify the present of cation in copper (II) sulphate solution.
Describe chemical tests to verify the present of anion in copper (II) sulphate solution.
Question 3
Preparation of salt
0.1 mol dm-3 hydrochloric acid
method of preparation of salt
Experiment 125.0 cm3 of 0.2 mol dm-3 sodium
hydroxide + phenolphthalein
Name of method:i.Titration
Experiment 11
10 cm3 of 1.0 mol dm-3 lead(II) nitrate solution
Excess potassium iodide solution
Name of method:Double decomposition(precipitation)
b.Experiment 1i.Name reaction Neutralization
ii.Chemical equationNaOH + HCl NaCl +H2O
iii. Colour change of phenolpthalein
Pink to colourless
iv. Calculate Volume of HCl needed
Mole of NaOH= 25 x 0.1/1000 =0.005
From the equation,
0.005 mol NaOH0.005 mol HCl
But mole = MV/1000
So V = mole x 1000/M
V = 0.005 x 1000/0.1
V = 50Cm3
c. Experiment II
i.Name of saltLead(II) iodide
Ii. Write Ionic equation
Pb 2+ + 2I- PbI2
Iii How pure salt is obtained from the reaction II?
- Filter the mixture
- Rinse residue with distilled water
- Dry between two filter papers
iv. Calculate maximum mass of precipitate X
Mole of Pb(NO3)2= 10x1 /1000
= 0.01 mol
But
0.01 mole Pb 2+ 0.01 mole PbI2
So mass of PbI2 = mole x mmass
= 0.01x(207+ 2(127))g
=4.61 g
Question 4Action of heat on salts
+
I. Name gas Q CARBON DIOXIDE name of COMPOUND x
Copper (ii) carbonate
Compound X
Copper (II) oxide
Gas Q∆
State the colour of
COMPOUND X COPPER(II) OXIDE
GREEN
BLACK
(III) Chemical equation for decomposition of compound X
CuCO3 CuO + CO2
(iv) If copper(II) nitrate is heated to replace compound X, write chemical equation
2Cu(NO3)2 2CuO+
4NO2+ O2
thank you
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