Question

Find the molecular mass of:
\[\left( a \right){H_2}S\] $\left( b \right)HCl$ $\left( c \right)N{H_3}$ $\left( d \right)C{l_2}$ $\left( e \right)C{H_3}COOH$ $\left( f \right)C{H_3}CHO$

Answer 1

:Hint: Atoms of different elements are important as their relative mass together forms the mass of the specific molecules. The molecular masses can be used for determining the mass of the specific compound needs to be used in the preparation of a solution.

Complete step by step answer:
The molecular mass of:
$\left( a \right){H_2}S \to $ The atomic mass of Hydrogen $\left( H \right)$ is $1$ and the atomic mass of Sulphur $\left( S \right)$ is $32$. Therefore, the main structure of ${H_2}S$ has two atoms of Hydrogen and one atom of Sulphur. It shows the molecular mass of ${H_2}S$ is \[(1 \times 2) + 32 = 34\]. There the molecular mass of ${H_2}S$ is $34units$.
$\left( b \right)HCl \to $ The atomic mass of Hydrogen $\left( H \right)$ is $1$ and the atomic mass of Chlorine $\left( {Cl} \right)$ is $35.5$. Therefore, the main structure of $HCl$ has one atom of Hydrogen and one atom of Chlorine. It shows the molecular mass of $HCl$ is $1 + 35.5 = 36.5$. The molecular mass of $HCl$ is $36.5units$.
$\left( c \right)N{H_3} \to $ The atomic mass of Nitrogen $\left( N \right)$ is $14$ and the atomic mass of Hydrogen $\left( H \right)$ is $1$. Therefore, the main structure of $N{H_3}$ has one atom of Nitrogen and three atoms of Hydrogen. It shows the molecular mass of $N{H_3}$ is $14 + (1 \times 3) = 17$. The molecular mass of $N{H_3}$ is $17units$.
$\left( d \right)C{l_2} \to $ The atomic mass of Chlorine $\left( {Cl} \right)$ is $35.5$. Here in the molecule there are two atoms of chlorine involved in the formation of $C{l_2}$. It shows the molecular mass of $C{l_2}$ is $35.5 \times 2 = 71$. The molecular mass of $C{l_2}$ is $71units$.
$\left( e \right)C{H_3}COOH \to $ The atomic mass of Carbon $\left( C \right)$ is $12$ , the atomic mass of Hydrogen $\left( H \right)$ is $1$, the atomic mass of Oxygen $\left( O \right)$ is $16$. In the formation of $C{H_3}COOH$ there are two atoms of carbon, two atoms of oxygen and four atoms of hydrogen involved. It shows that the molecular mass of $C{H_3}COOH$ is $12 + (1 \times 3) + 12 + 16 + 16 + 1 = 60$. Therefore, the molecular mass of $C{H_3}COOH$is $60units$.
$\left( f \right)C{H_3}CHO \to $ The atomic mass of Carbon $\left( C \right)$ is $12$ , the atomic mass of Hydrogen $\left( H \right)$ is $1$, the atomic mass of Oxygen $\left( O \right)$ is $16$. In the formation of $C{H_3}CHO$ there are two atoms of carbon, four atoms of hydrogen and one atom of oxygen involved. It shows the molecular mass of $C{H_3}CHO$ is $12 + (1 \times 3) + 12 + 1 + 16 = 44$. Therefore, the molecular mass of $C{H_3}CHO$ is $44units$.

Note:
The atomic mass can be used to calculate the molecular masses of all the given compounds. The different atoms involved in the formation of the given molecule plays an important role in it and all the atomic masses are additive while determining molecular mass.