Monday, January 13, 2014

UNDERSTANDING OF METALS AND NON METALS

OBJECTIVES


Name the following:

From the list of characteristic given below select the five which are relevant to metals and their compounds.



DEFINE


Minerals


Gangue


Ores


Metallurgy


Roasting


Sonorous.


Malleability.


Ductility.


Anodising.


Ionic bond.


Covalent bond.


Covalent compound.


Reactivity series of metals.


Calcination.


Electroplating .


Corrosion.


Alloy.


Galvanising.



Tinning.




GIVE SCIENTIFIC REASONS


Sodium is stored under kerosene.


Gold and silver are used to make jewellery.


Calcium floats over water during the reaction with water.


Ionic compounds have high melting and boiling points


Tarnished copper utensils are cleaned with lime juice or tamarind.


Copper is exposed to air.


Reason for use of fused cryolite (Na3AlF6) along with fluorspar (CaF2) which is added to the electrolytic mixture containing pure alumina.


Electrolysis of active metals like Na, K, Al is not carried out by using aqueous solution of their chloride.


Elements like gold, silver are found in free or native state.


Pure water is a poor conductor of electricity but aqueous solution of NaCl conducts electricity.


An aqueous solution of sodium chloride conducts electricity.


Ionic compounds are formed due to the combination of metals and nonmetals.


Some elements occur in free state while others occur in the combined state.


Sodium and chlorine are poisonous substances but sodium chloride is edible.


Aluminium oxide is an amphoteric oxide.



Kitchen articles like pressure cooker, pan etc. are anodized.



ANSWER THE FOLLOWING IN DETAIL



Sudha dipped a copper coin in a solution of silver nitrate. After some time she saw the silver shine on the coin. Why? Give the balanced chemical equation for the same.


Metal A has electronic configuration of (2,8,1) and metal B has (2,8,8,2) which is more reactive. Identify these metals and vie their reactions with dil HCl.


To obtain (zinc) Zn from zinc sulphide two chemical reaction are involved


When steam is passed over aluminium.


Extraction of copper from its sulphide ore.


Thermit reaction.


When magnesium reacts with hot water.



What happens when aluminium oxide dissolves in aqueous sodium hydroxide?


In the extraction of aluminium



Write two methods of preventing rusting of iron.



What is an alloy? Give two examples with their chemical composition.


Arrange the following metals in the decreasing order of chemical reactivity, Cu, Mg, Fe, Na, Ca, Zn.



Explain the formation of an ionic compound between metal and a non – metal by transfer of electrons with Mg as the metal and Cl as a non – metal to illustrate your answer.


An element X on reacting with oxygen forms an oxide X2O. This oxide dissolves in water and turns red litmus blue. State whether element X is a metal or a non – metal. Explain with proper example.


Explain the properties of ionic compounds.



Write a short note on anodizing.


Metallurgy

Ore (Text Book)

OXIDES OF METALS AND NON METALS

Distinguish between metals and nonmetals with respect to the following points.

Carbon dioxide and Ammonia.

We can obtain a fountain of ammonia gas.

Metals are good conductors, while nonmetals are poor conductors of Electricity.

Carbon dioxide is used as a fire extinguisher.

When carbon dioxide is passed through lime water, it first turns milky and then turns colourless.

A magnesium ribbon continues to burn brilliantly in a gas jar containing carbon dioxide.

Acidified solution of potassium dichromate turns green when H2S is passed through it.

Aluminium oxide is classified as an amphoteric oxide.

Metals have electropositive character.

Define

How carbon dioxide gas is prepared in the laboratory

Describe the method of preparation of hydrogen sulphide using Kipp’s apparatus.

Hydrogen sulphide gas.

Explain the stages involved in the extraction of cast iron.

Explain the stages involved in the preliminary treatment to concentrate iron ore.

State the physical properties of ammonia.

Give the physical properties of carbon dioxide.

Write two physical properties of Hydrogen sulphide.

State the uses of sulphur.

How does sulphur occur in nature?

Why must the anodes be replaced from time to time during the electrolysis of fused alumina?

Why alumina is dissolved in Cryolite for electrolysis?

Molecules of sulphur.

Monoclinic sulphur

Rhombic sulphur

Electrolysis of fused alumina

Bayer’s process for concentration of bauxite.

Blast furnace

Magnetic separator


Answer in one sentence

Write the Uses Of

Bleaching powder.

Plaster of Paris.

Alum

Blue vitriol

Green vitriol.

Limestone

Washing soda (Sodium Carbonate)

Baking soda (Sodium bicarbonate)

State The Uses Of

Bleaching Powder.

Plaster of Paris

Alum

Blue vitriol

Green vitriol

Lime stone

Washing soda

Baking soda


Write the scientific names and molecular formulae of the following.

Plaster of Paris is used in the laboratories for sealing and making the apparatus airtight.

Alum is used for purification of drinking water.

Copper sulphate crystals on heating turn to a white amorphous powder.

Ferrous sulphate crystals turn white on heating.

Plaster of Paris is used for making statues and to set the fractured bones at the right position.

Sodium bicarbonate is used in fire extinguisher.

Baking powder is used in the preparation of bread and cake.

Bordeauxmixture is sprayed on fruit trees.