Atoms, Molecules, Mixture and Compound
Atom may or may not exist in Free State.
Molecules exist in Free State.
Molecule is a combination of two or more like and unlike atoms.
Element is the pure form of the matter.
Element is composed of only one kind of atoms.
Total elements
are 118.
92 are found in nature while the
remaining elements are manmade.
Hydrogen is used for filling of weather balloons.
Sodium is used in sodium lamp.
Magnesium powder is used in the flesh light.
Carbon (graphite) is used in the manufacture of lead pencil.
Phosphorous is used in the manufacture of matches.
The impure
form of matter is called mixture.
Carbon dioxide is colorless gas which makes up about 0.03%
of the air.
Filtration, chromatography are the techniques for separation
of mixtures.
Out
of 118 elements, 20 elements are classified as non-metals.
Hydrogen,
helium, nitrogen and oxygen are gases.
Bromine is a liquid.
Compound is a substance, which is formed by the chemical combination of two
or more different elements in fixed ratio.
Filtration: It is used to
separate insoluble particles from liquid by filter paper.
During
filtration process the clear liquid is called Filtrate.
During
filtration process all those particles left behind the filter paper is called residue.
Sublimation: It is a process in which some solid substances, when heated, change
directly to the gases state without passing through the liquid state.
Example of sublimation substances are Iodine, Ammonium Chloride
and Nephthalene etc.
The
process of evaporation (عمل تبخیر) followed by condensation (عمل تکثیف) is called distillation (تقطیر یعنی قطرہ قطرہ
ٹپکانے کا عمل).
Chromatography is a modern technique used for the separation of mixture.
The symbol used for sodium is………………..
a) S
b) Sd
c) Na
d) N
Which of these is not a mixture……………….
a) Water
b) air
c) Tea
d) Alloy
Which method is usually used to separate colored substances from each other?
a) Distillation
b)Evaporation
c) Chromatography
d) Crystallization
Remaining solid on filter paper is known as…
a) Solution
b) Stone
c) Particles
d) Residue
Letter used to identify an element in periodic table is known as…………..
a) Formula
b) Idea
c) Symbol
d) Hint
