33 Science -- Metals

Write any three alloys in which copper is used. Also write composition and uses.

1 Answers

Any three alloys in which copper is used are:
a. Brass --------> Cu + Zn ---------> To make not bolts, tubes, medals, etc.
b. Bronze --------> Cu + Zn + Sn -----------> To make household utensils and coins.
c. Bell metal ---------> Cu + Zn -----------> To make bells and decorative items.

What are metals? Give any two examples.

Metals are elements which form electropositive ions by losing electrons.
For eg. Iron, copper, gold, etc.

Write any two differences between:

i. Minerals and Ores.

Minerals	Ores
It contains metals in more or less amount.	It contains metals in more amount.
All minerals are not ores.	All ores are minerals.

What is meant by metallugary?

The process by which we can get pure metals from their ores id called metallugary.

Write short note on occurrance of iron in nature.

Iron is of the reactive metals. So, it doesn't occur in free state in nature. It forms different types of compounds like oxides sulphides, chlorides, hydroxides, carbonates, etc. A little amount of iron is present in haemoglobin of our blood.

How is iron extracted? Describe in brief.

Iron is extracted by the following ways:
> It is extracted from haematite ore.
> it is collected from ore mines and crushed into fine powder.
> Non-magnetic dirts are separated by the electromagnetic separation method.
> Finally molten iron is obtained and further purified.

Write the chief ores of the following metals.

a. Iron: Haematite (Fe₂O₃)
b. Aluminium: Bauxite (Al₂O₃ . 2H₂O)
c. Copper: Copper phyrite "chalcopyrite" (CuFeS₂)
d. Silver: Argentite (Ag₂S)
e. Gold: Alluvial sand/soil

Write any three physical properties of the given metals.

a. Iron:
> It is good conductor of heat.
> Its specific gravity is 7.86.
> It is malleable and ductile.
b. Aluminium:
> It is good conductor of heat and electricity.
> its specific gravity is 2.7.
> It is highly malleable and ductile.
c. Copper:
>It is good conductor of heat and electricity.
> its specific gravity is 8.95.
> It is malleable and ductile.
d. Silver:
> It is good conductor of heat and electricity.
> its specific gravity is 10.5.
>...

Name the metals that can be obtained from the given ore:

a. Haematite: Iron
b. Bauxite: Aluminium
c. Argentite: Silver
d. Cuprite: Copper
e. Calaverite: Gold

How does rusting takes place on iron? Write with a balanced chemical eqn.

When iron reacts with air (oxygen), some chemical rxⁿtake place at normal temperature to form rust.

Arrange iron, gold, silver and aluminium in the increasing order with their melting and boiling point.

The order is given below:
Aluminium, silver, gold, copper, iron.

what is aquaregia? which element is found in aquaregia that dissolve gold?

The process of reacting hydrochloric acid (Hcl) and sulphuric acid (H₂SO₄) in the ratio of (3:1) is called aquaregia.
Calaverite element is found in aquaregia that dissolve gold.

Write any three uses iron, aluminium, copper, silver and gold.

Any three uses are:
a. Iron
> Make different household utensils.
> Catalyst for different chemical rxⁿ.
> Manufacture the steel.
b. Aluminium
>Make different household utensils.
> Make coins, medals.
> Cover of airplane, rocket, etc.
c. Copper
> Make electric wires and cables.
> Make coins and medals.
> Make household utensils.
d. Silver
> Make jewelry and other valuable ornaments.
> Make coins, medals, idols, etc.
> Make silver plating.
e. Gold...

Name the metal that is used for:

a. Making steel and weapon: (Iron)
b. Making silver paint and body parts of airplanes: (Aluminium)
c. Making fungicides and germicides: (Copper)
d. Making coins and idols: (Silver)
e. Making valuable ornament and medicines. (Gold)

Make a list of metals found in different parts of Nepal.

The metals found in different parts of Nepal are:
a. Iron ----------> Lalitpur, Bhojpur, Ramechap.
b. Copper ----------> Udayapur, Dhading, Solukhumbu.
c. Gold ---------> Rapti, Mustang, Kathmandu.
d. Magnesium -----------> Udayapur, Dolakha.
e. Cobalt ----------> Palpa, Gulmi.
f. Calcium -----------> Kathmandu, Makwanpur.
g. Bismuth -----------> Makwanpur (Bhimphedi)
h. Lead ----------> Lalitpur, Ganesh Himal (Rasuwa)

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