Question

How do you calculate the molar mass of pentanol, $C{H_3}{\left( {C{H_2}} \right)_3}C{H_2}OH$ ?

Answer 1

The molar mass of a substance is defined as the mass of a substance which is present in one mole of a substance. One mole of a substance contains a number of particles equal to the Avogadro’s number which is $6.023 \times {10^{23}}$.

Complete step by step answer:
The molar mass is related to the mole concept. The mass of substance present in $1mole$ of substance. It is calculated by adding the atomic masses of the elements present in a compound.
So at first we need to know the atomic masses of the elements which constitute the compound. The compound given in this question is pentanol. Pentanol is an organic alcohol compound. It is composed of an alkane and an alcohol functional group.
Thus in pentanol the alkane is the pentane and it is attached to the hydroxyl group. The $-ane$ is replaced by the suffix $-ol$ giving the name as pentanol.
The molar mass is determined; we need to determine the chemical formula of the compound pentanol. The chemical formula of pentanol is ${C_5}{H_{12}}O$. So from the chemical formula it is clear that pentanol is composed of three elements which are carbon, hydrogen and oxygen.
The atomic masses of carbon, hydrogen and oxygen are $12u$, $1u$ and $16u$ respectively. The molar mass is expressed in units of $gmo{l^{ - 1}}$.

**Hence the molar mass of pentanol is = $5{\text{ }} \times$ atomic mass of $C$ + $12{\text{ }} \times$ atomic mass of $H^+$ atomic mass of $O$.
$= 5 \times 12 + 12 \times 1 + 16 = 88g/mol.$ **

Note: The unit $u$ is used to express the atomic mass of elements. It is the synonym of $amu$ which stands for atomic mass unit. For convenience of calculation the mass of elements and compounds are represented in the g unit.