Question

How do you calculate the number of moles of solute?

Answer 1

For the calculation of moles of solute or any other substance we have to know the molecular weight and given weight of that solute, because relation between number of moles and weights are shown as follow:
${\text{n = }}\dfrac{{\text{W}}}{{\text{M}}}$

Complete step-by-step answer: For the calculation of number of mole of solute we have to use the equation which shows relation between moles (${\text{mol}}$) and weight in grams (${\text{g}}$) which is described as:
${\text{n = }}\dfrac{{\text{W}}}{{\text{M}}}$
Where, ${\text{n}}$ = No. of moles (in ${\text{mol}}$)
${\text{W}}$= Given weight of solute in grams (${\text{g}}$)
${\text{M}}$ = Molecular or molar mass of the given solute in grams per mole (${\text{g/mol}}$)
Whenever we have to calculate the number of moles of any substance, we have to divide the given weight (in ${\text{g}}$) of the substance to the molecular weight (${\text{g/mol}}$) of that substance.
As in the given question we have to calculate the number of moles of solute then in this condition by using equation (i) or through dividing the given weight of solute by the molecular weight of that solute as:
Moles of solute (${\text{mol}}$) = Given weight of solute (${\text{g}}$) / molecular weight of solute (${\text{gmo}}{{\text{l}}^{{\text{ - 1}}}}$)

Note: Here some of you may think that how the unit converts into moles on dividing the given eight to molecular weight, so the reason is that grams from numerical & denominator get canceled and only moles will get left.