Mole Concept Formula

Mole is the Latin word which means collection, or heap or pile.

Mole is defined as the amount of substance that contains as many atom , molecules, ions or particles as there are atom of 12g of carbon C- 12.

For example

We measure the substance in gram, kilograms, litter dozens etc.

Like.

1 dozen banana = 12    bananas

1 dozens apple = 12   apple

Similarly,

1 Mole of atom=    6.022× 1023 atom

1 Mole of molecule  =     6.022× 1023  molecule

( 6.022× 1023  number is known as Avogadro number it is denoted by Na)

Example:

1 mole of oxygen (O)  atom and Oxygen molecule ( O2)

1 mole of oxygen (O)  atom    =    6.022× 1023  oxygen atom

1 Mole of Oxygen molecule ( O2)  =   6.022× 1023  oxygen molecule

Atomic Mass

Mass of one atom of an elements called atomic mass.  OR

The total number of protons and neutron in an atom. OR

atomic mass unit (1u)=  exactly one twelfth (1/12th)  the mass of one atom of carbon-12 .

Gram atomic mass

The amount of substance whose mass in gram is numerically equal to the its atomic mass is called gram atomic mass of that substance.

Example:

Gram atomic mass of oxygen= 16g

Oxygen  (O) = 16u in atomic mass unit

Oxygen  (O) = 16g in Gram atomic mass

So,

Molar mass or Gram atomic mass

Example: Mass of hydrogen atom  is 1.66×10-24 g  thatis equal to 1u in atomic mass unit

Mass of 1 atom in gram =  A ×  1.66×10-24 g

(1.66×10-24 g  Is the mass of hydrogen atom given by relative or as a reference mass)

A = Atomic mass of atom or element

Mass of  of hydrogen atom in gram= A ×  1.66×10-24 ×Na

Mass of  6.022× 1023  of hydrogen atom in gram=  A ×  1.66×10-24 ×6.022× 1023  

Formulas :

Molar mass or gram atomic mass   = A× 1 = A gm

1.66×10-24 ×Na=  1

Gram Molecular Mass

The amount of substance whose mass in gram is numerically equal to its molecular mass of that substance.

For example;

Molecular mass of oxygen ( O2) = 16×2 = 32u

Gram Molecular mass of oxygen ( O2) =   32gm

Mole Concept Formulas

Formula-1

m = Given mass

M   = Molar mass

Q: calculate the number of mole 224 gm of Fe ?

Solution: 

Given mass=   224

Molar mass of Fe    =    56

Formula:   

n= number of mole

m = Given number

M= Molar mass

Q : Find the number of mole of atom 120g of calcium?

Solution: 

Given mass = 120

Molar mass of Fe  = 40

Formula:   

n=  number of mole

m = Given number

M= Molar mass

Formula-2

 

N=. Given  number of particles

N a =  Avogadro number

n= Number of moles

Q: Calculate the number of moles in 3.011×1023 atom of carbon dioxide?

Solution:

Given,

Given numbers of particles =3.011⨯1023

Avogadro number. = 6.022×1023

number of moles. =?

Formula;

Formula-3

Mass in gram= number of moles × Molar mass

m= n × M

Q: calculate the mass of 4 Mole of sodium?

Solution: given

n= 4

M=23

m= ?

Mass in gram= number of moles × Molar mass

m = 4 × 23

m=. 92gm

 

Q: calculate the mass of 5 Mole of carbon dioxide?

Solution : given

n= 5

M=44

m= ?

Mass in gram= number of moles × Molar mass

m = 5 × 44

m=. 220gm

Formula-4

m=   Given mass

M=   Molar mass

N a =  Avogadro number

Q : calculate the molecule of 2.3 g of sodium?

 Solution:

m=   Given mass of sodium 2.3g

M=   Molar mass. Of sodium is 23 g

N a =  Avogadro number. =6.022×1023

Number of molecule = 6.022×1022

Q: Calculate the 36g of water ?

Solution:

Molecule of water is H2O

= 2H +O

= 2×(1)+1×(16)

=. 2 + 16 = 18u

 

m=   Given mass of water36g

M=   Molar mass. Of Water is 18

N a =  Avogadro number. = 6.022×1023

Number of molecule = 2 ×6.022×1023

Number of molecule = 1.2044×1024

 Formula-5

 S.t.p. = Standard Temperature pressure

Volume occupied by 1 Mole that is molar volume of ideal gas at s. t. p. is 22.7 l

Q : calculate thenumber of Mole of Ne gas  45.5 litre at s.t.p.?

Solution:

Given;

Volume of Ne gas. =. 45.5l

Molar volume. = 22.7l

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