CHEMISTRY [1 Mark Question Answer]

Stainless steel—Iron, chromium, nickel

Duralumin—Aluminium and copper

Bronze—Copper and tin

Brass—Copper and zinc

It is a shiny grey metal, in solid state at room temperature. It can withstand high temperature because it has highest melting point among metals. Hence, it is used in electric bulbs.

Pure gold is a very soft metal. It cannot be moulded into ornaments so it is mixed with copper and nickel so that it becomes harder and bit cheaper also.

Impure diamond is used to cut glass becuase it is the hardest substance and can easily exert force required for cutting.

Graphite turns paper black that is why it is used in the leads of pencils.

Copper is ductile and a very good conductor of heat and electricity. This is the reason that copper is used in making electric cables.

Aluminium is used in making aircrafts because it is light and strong. It is mixed with other metals to make it stronger.

Magnesium is used in fire works because it bums with a dazzling light.

It is used in photographic films in the form of potassium iodide.
It is added to salt to make it iodized salt which is necessary for the growth of human body.

It is used by all living beings for breathing.
It is important for combustion.

It is used for making ornaments and coins.
It is used in the manufacture of electronic devices like computers, telephones, home appliances, etc.

It is used to make electric wires.
It is used to make utensils, cans, window fram’es, etc.

It is used to make pipes, tanks, railing, etc.
It is used in the construction of power transmission towers.

The homogeneous mixture formed by mixing a metal with other metals or nonmetals in certain proportion is called an alloy.

Use of argon :It is used for filling electric bulbs.

Use of helium :Helium is used for filling weather observation balloons.

A group of gases which do not react chemically with any other substance are called noble gases. They are helium, neon, argon, krypton, xenon and radon.

Uses of graphite :

• Graphite is used as pencil lead.
• It is used as a dry lubricant because it is extremely soft and does not bum even at high temperature.

Uses of iodine :

• Tincture of iodine is used for dressing wounds.
• Small quantities of iodine as sodium iodide or potassium iodide are extremely essential for the proper functioning of human body. It is used in the form of iodized salt.

Uses of chlorine :

• It is used for bleaching cotton and jute fabrics.
• It is used in the sterilization of drinking water.

Uses of oxygen :

• It is essential for respiration in plants and animals.
• It is essential for combustion of fuels.

Uses of nitrogen :

• It dilutes the activity of oxygen.
• The compounds of nitrogen are of vital importance to plant for growth.

Nitrogen.

Chlorine.

Graphite (form of carbon).

Bromine is liquid at room temperature.

Diamond is a form of carbon which is the hardest substance.

The elements which are either gases or soft solids, have no lustre, are non-malleable and non-ductile and bad conductors of heat and electricity are called non-metals.

Uses of mercury :

• It is used as a thermometric liquid in laboratory as well as clinical thermometers.
• Gold amalgam and silver amalgam are used in dentistry for filling tooth cavities.

Uses of magnesium :

• It bums with dazzling white flame and hence is used in fire works.
• It is used in the making of alloys, such as magnalium. This alloy is used in making frame of aeroplanes.

Uses of lead :

• It is used for making lead acid batteries used in all kinds of automobiles.
• It is used for making sanitary pipes.

Uses of aluminium:

• Aluminium foils are used for packing food stuff, medicines etc.
• It is used for making high voltage electric transmission wires.

Uses of zinc :

• It is used for galvanizing iron sheets to prevent iron from rusting.
• It is used for making alloys such as brass and bronze.