Question

The percentage of an element M is 53 in its oxide of molecular formula ${M_2}{O_3}$ . Its atomic mass is about
A. 46
B. 10
C. 19
D. 27

Answer 1

Hint: The atomic mass is the total mass of an atom. The sum of the numbers of protons and neutrons in the nucleus is called the mass number.

Complete step by step solution:
The molecular mass is the mass of a given molecule is measured by mass spectrometry and it can be used to determine the composition of elements in the molecule. The molar mass is defined as the mass of a given substance divided by the amount of a substance and is expressed in g/mol. The sum of the atomic masses of all atoms in a molecule, based on a scale in which the atomic masses of hydrogen, carbon, nitrogen, and oxygen or any other element present in the compound. Unit of mass often used is Dalton (Da) or unified atomic mass unit (u) when describing atomic masses and molecular masses.
100 gm of metal oxide contains 53 g of metal.
Let the atomic mass of M is “x’
Molecular weight of compounds is calculated by the total number of atoms constituted in the elemental of the compound.
Molecular weight of compound $ = 2x + (16\times3)$
=$2x + 48$
% of weight $$ = \dfrac{{mass\, of\, solute}}{{Total\, Mass}}\times 100$$
$53$ =$$\dfrac{{2x}}{{2x + 48}}\times 100$$
$x = 27$

Hence the correct option is option (D). 27

Note:
Molecular mass is the mass of a molecule, which is the sum of its constituent atomic masses. Molar mass is an average of the masses of the constituent molecules in a chemically pure but isotopically heterogeneous ensemble.