Question

WHAT IS MOLE CONCEPT??
GIVE EXAMPLES​

Answer 1

MOLE CONCEPT :-

To understand mole concept, one should know what actually a mole is.

Mole means heap/collection/pile.

A mole of atoms is a collection of atoms whose total mass is the number of grams equal to the atomic mass.

We can also say that, a mole = 6.023 x $10^{2}$ particles of the same matter.

A mole represents a definite number of particles (atoms, molecules, ions, electrons). The definite number is 6.023 x $10^{2}$ and this is known as Avogadro Constant. It is denoted by $N_{A}$.

For example:-  The atomic mass of Sodium(Na) is 22.9 g. This means that the mass of 1 mol of sodium is exactly 22.9 g and will contain 6.023 x $10^{2}$ of 22.9 g of Na atoms.

Formula to calculate no. of moles :-

n = N/$N_{A}$

where

n = number of moles

N = total number of atoms/molecules

$N_{A}$ = Avogadro Constant

    or

n = mass of the element/gram-atomic mass of the element.

gram-atomic mass of an element means the mass of 1 mole of that element.

Why do we need mole concept ?

=> We know that basic unit of a chemical substance is an atom or a molecule. We also know that even 1 g of an element contains a lot of atoms. So, in order to decrease the difficulty in measurements and increase the efficiency  for conducting experiments, mole becomes a handy tool. Since, an equal no. of moles of different elements contains an equal no. of atoms, it becomes quite easy to express the amounts of elements in terms of mole.

Some examples related to Mole Concept :-

Q.1 Calculate the number of moles in 5.75 g of sodium.

Ans. 1 mol of Na atom = 23 g (round-off)

        23 g of Na = 1 mol of Na

        5.75 g of Na = ( 5.75/23 ) mol of Na = 0.25 mol

Q.2 The density of liquid mercury is 13.6 g/$cm^{3}$. How many moles of mercury are there in 1 litre of the metal ?

Ans. Mass of Hg (in grams) = density x volume

                             = 13.6 g/$cm^{3}$ x 1000 $cm^{3}$

                             = 13600 g

 No. of moles of Hg = 13600/200 = 68     { Atomic mass of Hg = 200 }

#answerwithquality #BAL

Answer 2

Answer:6.023×10^23

Explanation:it is defined as amount of substance which contain avogadra number of 6.023×10^23 number of particle .the mole concept can be converted into mass,volume

For ex:for an elements

1 mole of element=atomic mass of elements=2.24×10^-2m^3

When you use litre 22.4 litre

=6.023×10^23 no of particles

I take 1 mole of cu=atomic mass of cu is 63.5=2.24×10^-2m^3=6.023×10^23

For an compound

1 mole of compound =molecular mass of compound = 2.24×10^-2m^3=6.023×10^23 no of particles

Compounds means no of elements bonded together

Ex:co2

In chemistry amount of substance is expressed in mole.in a chemical reaction all reactant and product combined together with definite number of mole.

Calculation of moles:

No of moles=given mass /molecular mass(for compounds)or atomic mass(for elements)

Ex sum:

No of moles present in 90gm of water (h20)

1 mole of h20=molecular mass of h20

H20=no of hydrogen 2×1 (atomic mass of hygrogenl+ oxygen 1×16 (atomic mass)

=2+16

=18 gm

1 molecular mass of water =18gm

Given mass =90

Use the above formula

No of moles=90/18=5 moles