Mole Concept Basic - Practice Questions & MCQ

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

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Here G.m.m. = Gram molecular mass

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• Volume of one mole of any gas is equal to 22.4 litres of dm3 at STP. It is known as molar volume.

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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 10²³  molecules 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:

1. Total number of Molecule = mole(n) x N_A

2. Total number of Atoms = mole (n) x N_A x No. of atoms present in one molecule 

3. Total number of Electrons = mole (n) x N_A  x No. of electron present in one electron

4. 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:

1. Vapour Density method -

1. 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 

2. Graham Diffusion Method - 

Here r₁ ,  r₂ are rates of diffusion for two species while M₁, M₂ are their molecular masses respectively. 

3. Colligative Properties -

Here,

V = Volume in litre

W = Weight in grams 

R = Universal gas Constant

T = Given Temperature

m = Molar mass