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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