Question

How many grams are there in $5$ moles of Oxygen?

Answer 1

The amount of substance can be expressed in different quantities like moles or number of atoms or grams.
Mole contains $6.032 \times {10^{23}}$ atoms or molecules. The $1$ mole of a molecule contains the grams of substance which is equal to the molar mass of that molecule.
Thus, to determine the amount of grams present in moles, the number of moles should be multiplied with molar mass of the molecule.

Complete answer:
Periodic table is the representation of elements arranged in the increasing order of atomic numbers.
The periodic table consists of a total of $118$ elements.
These elements are arranged in vertical columns called groups and horizontal rows called periods.
There are $7$ periods and $18$ groups in the periodic table.
Oxygen is an element belonging to ${16^{th}}$ group and ${2^{nd}}$ period.
Oxygen has the atomic number of $8$.
Oxygen molecule exists as a dimer of elemental oxygen and has the molar mass doubled to $16$.
The molar mass of the oxygen molecule will be $32$.
Given oxygen contains 5 moles.
We know that $1$ mole of oxygen contains 32 grams of oxygen.
Thus, $5$ moles of oxygen contain $32 \times 5 = 160$grams of oxygen.
Thus, $5$ moles of oxygen contain $160$ grams of oxygen.
When the elemental oxygen is taken, it has a molar mass of $16$.
Thus, $5$ moles of elemental oxygen contain $16 \times 5 = 80$grams of elemental oxygen.

Note:
The molar mass should be multiplied by number of moles to determine the number of grams present in a given number of moles.
The molar mass should be taken clearly.
The molar mass of elemental oxygen will be different from molecular oxygen.