Question

The total number of gram molecules of $S{O}_{2}C{l}_2$ in $13.5g$ of sulphuryl chloride is:
(A) $0.1$
(B) $0.2$
(C) $0.3$
(D) $0.4$

Answer 1

Hint: Gram molecules can be defined the same as that of a mole. Gram molecules are the total number of molecules in one mole of substance.Gram molecule is defined as the number of grams of a substance that is the same as the relative molecular mass of that substance.

Complete step by step answer:
First of all, let's understand about the chemical compound sulfuryl chloride. It is an inorganic compound with the chemical formula $$S{O}_{2}C{l}_2$$. It is a colorless liquid with a pungent smell at the room temperature. Sulfur chloride is the source of chlorine gas. The IUPAC name of $$S{O}_{2}C{l}_2$$ is sulfuryl dichloride.
In the question, we have to find the gram molecules of $13.5g$ of $$S{O}_{2}C{l}_2$$. Gram molecules are the same as molecules. Gram molecules are defined as the number of moles present in the given mass of the substance.
i.e., $$GramMolecules={\displaystyle \frac{givenmassof\text{ substance}}{molecularmassof\text{ substance}}}$$ …. (i)
The molecular mass of a substance is the average relative mass of its molecules as compared with an atom of carbon $-12$ isotope or for a compound, it is defined as the combined atomic mass of all elements present in the compound. So, the molecular mass of $$S{O}_{2}C{l}_2$$ can be calculated as
$$1\times atomicmassofsulphur+2\times atomicmassofoxygen+2\times atomicmassofchlorine$$

We know that atomic masses of sulphur, oxygen and chlorine are $32g,16g\mathrm{\&}35.5g$ respectively. Thus, the molecular mass of $$S{O}_{2}C{l}_2$$ becomes = $$1\times 32+2\times 16+2\times 35.5=135g$$
Gram molecules = ${\displaystyle \frac{13.5}{135}}=0.1$
Hence, the answer is option (A).

Note:
The molecular mass of a substance expressed in grams is called the gram molecular mass. This amount is also called one gram molecule.The molecular mass (m) is the mass of a given molecule: it is measured in daltons (Da or u). Different molecules of the same compound may have different molecular masses because they contain different isotopes of an element.