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Mole Concept Basic - Practice Questions & MCQ

Edited By admin | Updated on Sep 18, 2023 18:34 AM | #JEE Main

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  • MOLE CONCEPT AND MOLAR MASS is considered one the most difficult concept.

  • 39 Questions around this concept.

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If we consider that 1/6, in place of 1/12, mass of carbon atom is taken to be the relative atomic mass unit, the mass of one mole of a substance will

The number of water molecules is maximum in :

If Avogadro number NA, is changed from 6.022 x 1023 mol-1 to 6.022 x 1020 mol-1, this would change :

The number of molecules and moles in 2.8375 litres of \mathrm{O}_{2} at STP are respectively

A sample of $\mathrm{CaCO}_3$ and $\mathrm{MgCO}_3$ weighed $2.21 \mathrm{~g}$ is ignited to constant weight of $1.152 \mathrm{~g}$. The composition of mixture is: (Given molar mass in $\mathrm{g} \mathrm{mol}^{-1} \mathrm{CaCO}_3: 100, \mathrm{MgCO}_3: 84$ )

Molar Mass = Vapour density X 2 , is valid for :

How many atoms are contained in a mole of 2- HYDROXY-PROPANOIC ACID (Lactic acid).

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How many volume will $\mathrm{CO}_2$ gas will occur in 88 g of its at STP?

Number of moles in 80 g of Calcium is

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Number of atoms in 400.78 grams of Ca ( At wt of Ca is $40.078 \mathrm{~g} / \mathrm{mole}$ )

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 or molar mass which is the mass of 1 mole of any substance

  • \mathrm{Mole = \frac{(\textrm{Volume of substance in litre}) }{22.4\ litre}}

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

  • \mathrm{Mole = \frac{\textrm{Number of identities}}{\textrm{Avogadro's number}}}

 

 

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 NA

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

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

  4. Total charge on any ion = mole (n) x NA x charge on one ion x 1.6 x 10-19 C

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MOLE CONCEPT AND MOLAR MASS

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