Introduction
Nowadays, different online calculators are available online to carry out stoichiometric calculations. These calculations which took a lot of effort to solve are today carried out in the blink of an eye. This is the magic that happens when science and technology are combined. A mole calculator is one of these various calculators that is used to calculate the number of moles present in a certain mass of a substance. Continue reading to learn the concept of mole and how it is calculated.
Importance of mole calculation
A mole is the SI unit of mass of a substance and is expressed as “mol”. It is a constant value and is equal to Avogadro’s number (6.022 x 1023) of atoms, ions, or molecules of a substance. the number of moles of a substance is calculated to estimate the amount of solute in a given solution.
It is also used to express the amount of a substance used or required to carry out a chemical reaction. For example, if you want to carry out the neutralization reaction of sulphuric acid and barium hydroxide. To calculate the exact required amount of both reactants, first balance the chemical equation of the reaction.
$$H_2SO_4\;+\;Ba(OH)_2 \;H_2O\;+\;BaSO_4$$
One mole of sulfuric acid neutralizes the one mole of barium hydroxide. So the reactants are used in equal amounts (1:1). Moreover, while making molar solutions, the amounts of solute and solvent are taken in moles and then converted to grams. Moles are also used to calculate the molarity of a solution.
Calculation of number of Moles
The number of moles of a given substance is calculated manually using the given formula
Moles = Mass / Molar mass
Mass = Moles x Molar mass
Molar mass = Mass / Moles
All these three units are interconvertible. If the two values are given, then the third value can be calculated. Or you may use the mole calculator to get the answer. Simply enter the given mass of the substance and click the “calculate” button. Now let us see some examples of mole calculation
Example # 1
how many moles of calcium carbonate (CaCO3) are present in the solution when 40 g of solute is used?
Formula
Moles = mass/molar mass
Molar mass of calcium carbonate = 100 g/mol
Moles = 40 / 100 Moles = 0.4 mol
Answer; 0.4 mol of calcium carbonate is present in the solution when 40 g calcium carbonate (CaCO3) is added.
Example # 2
what would be the molarity of a solution (1L) containing 80 grams of Ca(OH)2 (calcium hydroxide)?
Formula
Moles = Mass / molar mass
Moles = 80 / 74
Moles = 1.08 mol
Molarity = Moles / Volume of solution
Molarity = 1.08 / 1
Molarity = 1.08 mol / L
Answer; The molarity of the above-given solution is 1.08M.
