Question

How do you convert grams to moles and moles to grams?

Answer 1

Hint: For the conversion of any substance or quantity from grams to moles or moles to grams, first of all we have to know about the relation between those two given parameters or units.

Complete Solution :
Symbolically moles is denoted as ‘mol’, which is the S.I. unit of measurement of quantity of any substance.
- Symbolically gram is denoted as ‘g’, which is the S.I. unit of measurement of mass of any substance.
-Relation between moles and grams can be shown by the following formula:
${\text{n = }}\dfrac{{\text{W}}}{{\text{M}}}$ ………………….. (i)
Where, ${\text{n}}$ = No. of moles of the substance in moles $\left( {{\text{mol}}} \right)$,
${\text{W}}$ = Given weight of the substance in grams $\left( {\text{g}} \right)$,
${\text{M}}$ = Molecular or molar mass of the given substance in grams per moles $\left( {{\text{g/mol}}} \right)$.
-Whenever we have to convert any quantity from grams to moles, then from the equation (i) it is clear that we divide the given weight/mass of the substance by the molecular weight/mass of that substance to get moles of substance.
${\text{n = }}\dfrac{{{\text{W(g)}}}}{{{\text{M(gmo}}{{\text{l}}^{ - 1}})}}$
-Whenever we have to convert any quantity from moles to grams, then from equation (i) it is clear that we multiply the moles of the given substance to the molecular weight/mass of that substance to get grams of substance.
${\text{n(mol)}} \times {\text{M(gmo}}{{\text{l}}^{ - 1}}){\text{ = W(g)}}$

So, the correct answer is “Option B”.

Note: During the conversion of grams to moles and moles to grams of any substance always write the S.I. units of each measurement, otherwise you may get confused in the units of given weight and molecular weight of the substance.