Question

The formula unit mass of the substance is the:
(A). Sum of the atomic masses of all atoms in a formula unit of a compound
(B). Relative atomic masses of atoms
(C). Equal to the numerical value of the atomic mass
(D). None of these

Answer 1

Hint: The mass of the substance is the internal property of the substance. An object is made up of a large number of the atoms. The mass of the sum of all the atoms is the mass of the object. The unit mass of the substance is the mass of one atom of the substance.

Complete step-by-step answer:

The atom is the unit identity of the matter. The atoms consist of two regions, nucleus and electrons. The nucleus is the central positive charge and the electron revolves around the nucleus. The nucleus comprises the positively charged proton and neutral neutrons. The number of protons in the nucleus of the atom is equal to the number of electrons revolving around the nucleus.
More than two atoms combine to form the compound. Thus, the unit mass is equal to the sum of the atomic masses of all atoms in a formula unit of a compound.
Option A is correct.

Note: Relative atomic mass is a fraction of the average mass of one atom of element to the twelth mass of the atom Carbon-12.
The compound consists of more than one number of the elements. So, it cannot be counted as the numeric value of the atomic mass of the atom.