Write a note on 'Mole Concept'.
Answers
Explanation:
The mole is the unit of measurement in
the International System of Units (SI) for
amount of substance. The unit is
defined as the amount of a chemical
substance that contains as many
representative particles, e.g., atoms,
molecules, ions, electrons, or photons,
as there are atoms in 12 grams of
carbon-12 (12C), the isotope of carbon
with standard atomic weight 12 by
definition. This number is expressed by
the Avogadro constant, which has a
value of
7023602214085700000 6.0221408
57 x 1023 mol-1, which is just over 602
sextillion (thousand million million
million). The mole is one of the baseunits of the SI, and has the unit symbol mol.
The mole is widely used in chemistry as
a convenient way to express amounts
of reactants and products of chemical
reactions. For example, the chemical
equation 2 H2 + O2 + 2 H2O implies
that 2 moles of dihydrogen (H2) and
1 mole of dioxygen (O2) react to form
2 moles of water (H2O). The mole may
also be used to express the number of
atoms, ions, or other elementary
entities in a given sample of any
substance.
The concentration of asolution is commonly expressed by its
molarity, defined as the number of
moles of the dissolved substance per
litre of solution.
The number of molecules per mole is
known as Avogadro's constant, and is
defined such that the mass of one mole
of a substance, expressed in grams, is
equal to the mean relative molecular
mass of the substance. For example,
the mean relative molecular mass of
natural water is about 18.015, therefore,
one mole of water has a mass of about
18.015 grams.
The term gram-molecule was formerly
used for essentially the same concept.The term gram-atom has been used for a related but distinct concept,
namely a quantity of a substance that
contains Avogadro's number of atoms,
whether isolated or combined in
molecules.
Thus, for example, 1 mole of
MgBr2 is 1 gram-molecule of MgBr2 but
3 gram-atoms of MgBr2.
Explanation:
A mol (symbol mole) is define as the amount of substance that contains as many atoms, ions, molecules, electrons or any other elementary entities has there are carbon atoms is exactly 12 gm of .the number of atoms in 12 gm of is called Avogadro number .