Question

What does one gram atom of oxygen represents:
A.One mole of $O$
B.One mole of ${O_2}$
C.One mole of ${O_3}$
D.None of these

Answer 1

One gram atom means the mass of one mole of an element equal in grams to the atomic weight. One gram atom of oxygen is defined as the atoms present in one gram of oxygen atom.

Complete step by step answer:
First of all we will define the terms like one gram atom, one gram molecule and AMU units.
One gram atom: The mass of one mole of an element equal in grams to the atomic weight.
One gram molecule: It is defined as the number of grams of a substance i.e. molecular mass of substance.
Number of atoms present in one mole: Mole is the unit of measurement for the amount of substance.
In one mole there are $6.022 \times {10^{23}}$ particles which may be atoms, molecules, etc.
AMU in grams: A carbon atom weighs $12$ AMU, and one AMU is equal to $1.66 \times {10^{ - 24}}grams$.
Molar concentration: It is defined as the number of moles per unit volume.
Mole fraction: It is defined as the ratio of number of moles of solute or solvent to number of total moles of the solution.
So by using these terms we can say that one gram of oxygen will represent one mole of oxygen. Hence option A is correct.

Note:
The mole is an amount unit similar to familiar units like pair, dozen, gross, etc. It provides a specific measure of the number of atoms or molecules in a bulk sample of matter. A mole is defined as the amount of substance containing the same number of discrete entities (atoms, molecules, ions, etc.)