Chemistry

Molarity (M)


The molarity of a solution, or concentration in quantity of matter (mol / L), is the ratio between the number of moles of solute and the volume of the solution in liters.

Where:
M = molarity (mol / L)
no1= number of moles of solute (mol)
V = volume of solution (L)

The calculation of molarity is made by the above formula or by rule of three. Another formula we use is to find the number of moles of a solute:

Where:
n = number of moles (mol)
m1 = mass of solute (g)
MM = molar mass (g / mol)

Example: What is the molarity of a 3L solution with 87.75g NaCl?

                    

                  
                

We can use a single formula uniting the molarity and number of moles:

Where:
M = molarity (mol / L)
m1 = mass of solute (g)
MM1= molar mass of solute (g / mol)
V = volume of solution (L)