Question

What is the molar mass of magnesium oxide?

Answer 1

We know that the molar mass of the substance is the weight of one mole of the sample. In order to calculate the molar mass of the substance, we need to add the atomic masses of all the atoms within the molecule.

Complete answer:
Here, in the given question we need to calculate the molar mass of magnesium oxide. The molar mass, also referred to as molecular weight, is the sum of the atomic weight of all the atoms present in the given molecule. We can also say it is the sum of the molecular weights of all the elements present.
Also, to calculate the molar mass of magnesium oxide, we should know about the chemical formula of magnesium oxide, $MgO$. Then, we should know the molecular weights of magnesium and oxygen given in the periodic table.
The molecular weight of the element magnesium is $24.31g/mol$
The molecular weight of the element oxygen is $16g/mol$
Molar mass of magnesium oxide, $MgO$ = $16\,\, + \,\,24.31\,g/mol$
Molar mass of magnesium oxide, $MgO$= $40.31\,g/mol$
Therefore, the molar mass of magnesium oxide is $40.31\,g/mol$.

Note:
Always remember that the molar mass which is also referred to as molecular weight is the weight of one mole of substance. One mole of substance contains $6.023 \times {10^{23}}$ entities. These entities can be atoms, molecules or ions. A mole is just a standard value to calculate different things in chemistry just like one dozen contains twelve entities. Mole is used to calculate size of the smallest entities quantitatively. Molar mass is always expressed in grams (g) and Kilograms (Kg).