What is the Molarity of Pure Water?

Chemistry is a branch, which comprises of the exploration of the structuring of natural elements, their properties and reactions to other substances. In addition, creating correct solutions is essential for any chemistry lab. Any solution needs to have correct combination and be fit for results to be precise. So lets see more about Molarity, a term which us used to evaluate the preciseness of a solution.

What is Molarity?

Molarity is a unit for measuring concentration of a solution. When it comes to defining the molarity of a solution, it states about the amount of an element or substance that can be dissolved in a particular amount of a solution.

When an element or solute is dissolved in a solution, it brings change in the volume of the solution.  As a result, the solution after dissolving the solute is regarded while measuring molarity. The molarity is measured in moles/liter or mol/l.

How to Calculate Molarity?

The standard formula for calculating molarity is

Mole = Mass of solute / Molar mass of the solute.

Mole – In chemistry, Mole is a standard unit, which is used for evaluating large amounts of very small-size elements like atoms, molecules, etc.

Molar mass – Molar mass is a measuring unit that allows the researchers to compute the weight of a chemical element or compound. Molar mass is the total of the atomic masses of all the elements in a method. It is stated in g/mol.

Steps to calculate molarity:

Step 1 - First find out the basic formula to calculate molarity. Its formula is

Molarity = Number of moles of solute (element or substance dissolved in solution) / solution in litres (total quantity of solution)

Step 2 - Second step is to find the number of moles and the quantity of solution in litres. In case you are not given the number of moles, but you have the amount and mass of the solution, you can use those figures to find out the number of moles.

Step 3- Now third step is to evaluate solute’s molar mass. To calculate the number of moles from the weight (in grams) of the solute that has been used, find the molar mass of the solute. You can find that by totalling the molar masses of every element, which is the part of the solution. To find the molar masses of each element in grams, refer to the periodic table.

Step 4- Once you have found out the molar mass of the solute, multiply the value of molar mass of solute expressed in grams to (1/molar mass of solute). This way you will be able to find the number of moles for the solute.

Step 5 - Now to find the molarity, you would have to divide the number of moles of the solute by the quantity of solution (in litres).

Molarity = Moles of solute / Quantity of solution (litres)

Molarity of Pure water

To calculate the molarity of pure water::

Molar mass of water = 18 g/mol

Density of water = 1000 g/L

Now divide, Density by molar mass of water, i.e.

Morality of pure water = 1000 /18 = 55.55 (mol/L).

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