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Easy Chem 10[ Salt ]

Name: .... Form: 5.

1. Zinc nitrate salt is prepared by adding zinc oxide powder into 50 cm3 nitric acid 1.0mole dm-3 in a beaker. The nitric acid is heated while doing the experiment. Mixture

is stirred during the experiment and zinc oxide is added until it is excessive in the

beaker to make sure that acid is finished.

(a) Draw a set of apparatus to shows how this experiment can be done at lab.

[ 2 marks ]

(b) Why the acid is heated in this experiment.

[ 1 marks ]

(c) How do you know that the zinc oxide is excess in this reaction.

[ 1 marks ]

(d) How do you separate the excess zinc oxide from the solution formed.

[ 1 marks ](e) Write the chemical equation of this reaction.

[ 1 marks ](f) What is the colour of zinc nitrate solution?

[ 1 marks ](g) Name one salt that can be prepared by this method.

[ 1 marks ]

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(h) Zinc nitrate crystal produced is heated very strongly until there is no changes

observed.

(i) State the observations while doing the heating.

[ 2 marks ]

(ii) Write the chemical equation of this reaction.

[ 1 marks ]

(i) Why does zinc nitrate crystal cannot be prepared by heating zinc nitrate

solution until it is dried?

[ 1 marks ]

(j) Lead (II) iodide can be prepared by just adding lead (II) nitrate solution to

potassium iodide solution.

(i) Write the ionic equation of the reaction.

[ 1 marks ]

(ii) State the observation of this reaction.

[ 1 marks ]

(iii) State the name of this reaction.

[ 1 marks ]

(iv) How do you dry the salt produced.

[ 1 marks ]

(k) Suggest the substance to prepare the following salt by writing balancechemical equations.

(i) Calcium sulphate

(ii) Copper (II) nitrate

(iii) Lead (II) carbonate

[ 3 marks ]

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Answer

1.(a)

(b) To increase the rate of reaction.

(c) The zinc oxide does not dissolve in nitric acid / There is excess zinc oxide inthe beaker.

(d) Filter

(e) ZnO + 2HNO3 Zn(NO3)2 + H2O(f) Colourless

(g) Copper (II) sulphate (etc. it must be soluble salt)

(h) (i) 1. A yellow solid when hot and white when cold is produced.2. Brown gas are released.

(ii) 2Zn(NO3)2 2ZnO + 4NO2 + O2

(i) Zinc nitrate decompose when it is heated very strongly.(j) (i) Pb2+ + 2I- PbI2

(ii) Yellow precipitate is formed

(iii) Precipitation reaction / Double Decomposition Reaction

(iv) By pressing between two filter paper

(k) (i) 2Ca(NO3)2 2CaO + 4NO2 + O2

(ii) CuO + 2HNO3 Cu(NO3)2 + H2O

(iii) Pb(NO3)2 + Na2CO3 PbCO3 + 2NaNO3

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spatula

Nitric Acid

Glass Rod

Zinc oxide

Beaker

Heat

Tripod stand

Wire Gauze