Molar Concentration Formula and Examples

Molar Concentration Formula :

Molar concentration is the most effective way of describing solute concentration in solution. Molarity is described as the total number of moles of solute dissolved in per liter of solution,i.e., M = mol/L.  All moles measurements are applied to determine the volume of moles in the solution that is the molar concentration.

Molar concentration=Amount in moles/Volume of solution

where,

M→molar concentration

n→ moles of solute

V→liters of solution

Sample Examples :

Example 1:

Calculate the molar concentration of NaoH for the reaction between Hcl and  NaoH ?

Solution :

The balanced chemical equation can be framed as

Hcl+NaoH →Nach +H2o

For an acid

n(Hcl|)=(35.0/1000dm3)*0.250 mol dm-3

=8.75*10-3 mol

The mole ratio NaoH:Hcl=1.1

The amount of NaoH present in moles is 8.75*10-3  mol

Now we have the equation

Molar concentration=Amount in molesw/volume of solution

First convert the volume of aqueous NaoH into dm-3

25cm3=25/1000dm3

=25*10-3dm3

Therefore the molar concentration of NaoH

=8.75*10-3/25.0*10-3

Molar concentration of Nao=0.350 mol dm-3

Example 2 :

Calculate the concentration into geq/L? In a concentration of Ca(HCO3)2 is 0.85 gmol/L.

Solution :

[C] = 0.85 gmol/ L

[C]eq = [C][MM] / eq.mass

MM = 40.1(2) + 2{1+12+3(16)}

= 202.2

Number of reference species = 2

Therefore, eq.mass = Ca(HCO3)2 / 2

= 202.2 / 2

[C]eq = 0.85[202.2] / 202.2/2

= 1.7 geq/L

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