Mole Concept Basic MCQ - NEET Practice Questions & Answers

Quick Facts

MOLE CONCEPT AND MOLAR MASS is considered one the most difficult concept.
50 Questions around this concept.

Concepts Covered - 1

MOLE CONCEPT AND MOLAR MASS

Mole:

A mole is a unit that represents 6.023 x 10²³ particles, atoms, molecules or ions, etc., irrespective of their nature.
Mole is related to the mass of the substance, the volume of gaseous substance and the number of particles
$\mathrm{Mole = \frac{W}{M} = \frac{\textrm{(Wt. of substance in gm.) }}{(\textrm{Molar mass of substance (G.m.m)})}}$

Here G.m.m. = Gram molecular mass

$\mathrm{Mole = \frac{(\textrm{Volume of substance in litre}) }{22.4\ litre}}$
Volume of one mole of any gas is equal to 22.4 litres of dm3 at STP. It is known as molar volume.
$\mathrm{Mole = \frac{\textrm{Number of identities}}{\textrm{Avogadro's number}}}$
$\mathrm{Mole =\frac{ PV }{RT }}$

Here P= Pressure in atmosphere, V = Volume in litre, T = Temperature in Kelvin, R = Universal gas constant

Relationship of Mole:

A mole of any substance (like O₂) stands for:

6.023 x 10²³molecules of O₂
2 x 6.023 x 10²³ atoms of Oxygen
32 gm of Oxygen
22.4 litre of O₂ at STP.

To Find the Total Number of Identities:

Total number of Molecule = mole(n) x N_A
Total number of Atoms = mole (n) x N_A x No. of atoms present in one molecule
Total number of Electrons = mole (n) x N_A x No. of electron present in one electron
Total charge on any ion = mole (n) x N_A x charge on one ion x 1.6 x 10^-19 C

Determination of Molar mass:

Vapour Density method -

Vapour Density of gas is defined as the ratio of the weight of certain volume of a gas to the weight of the same volume of hydrogen at the same temperature and pressure

$\mathrm{\textrm{Vapour density of a gas} = \frac{\textrm{weight of V litres of the gas}}{\textrm{Weight of V litres of } H_2 \textrm{ at the same temperature and pressure}}}$