Question

Calculate the number of moles of water in 366g $BaC{l_2}.2{H_2}O$

Answer 1

The mole is the unit of measurement for the amount of substance in the International System of Units. A mole of a substance or a mole of particles is defined as exactly $6.022 \times {10^{23}}$ particles, which may be atoms, molecules, ions or electrons.

Formula used:
$Number\,of\,moles = \dfrac{{given\,mass}}{{molar\,mass}}$

Complete step by step answer:
Mole, also spelled as mol, is a standard scientific unit for measuring large quantities of very small entities such as atoms, molecules or other specified particles. The word mole was introduced by Wilhelm Ostwald in 1896. He received the Nobel prize in Chemistry in 1909 for his scientific contributions to the fields of catalysis, chemical equilibria and reaction velocities. The number of moles in a given sample can be calculated by dividing the total mass of the sample by the molar mass of the element/compound. Therefore, the mass of one mole of an element will be equal to its atomic mass in grams. When dealing with reactions that take place in the solutions, the concept of molarity is useful. It is defined as the number of moles of solute in a liter of solution. Now, let’s find the number of moles of water in 366g $BaC{l_2}.2{H_2}O$.
Molecular weight of $BaC{l_2}.2{H_2}O = 244g$.
So, 244g of $BaC{l_2}.2{H_2}O = 36g\,{H_2}O = 2mole\,of\,{H_2}O$
Therefore, 366g $BaC{l_2}.2{H_2}O$, according to the formula will be,
$= \dfrac{{2 \times 366}}{{244}}$
=3 Moles of ${H_2}O$

Note: The concept of mole helps to put the qualitative information about what happens in a chemical equation on a macroscopic level. The mole can be used to determine the simplest formula of a compound and to calculate the quantities involved in a chemical reaction.