Question

How many moles of atoms are there in $9.0g$ of Aluminum?

Answer 1

To find the number of moles we must know about the molecular weight of the given compound or element or atom. Also there must be a given mass or weight in the question. Avogadro number is the number of units in one mole of any substance equal to $6.02214076 \times {10^{23}}$.

Complete answer:
To solve this question we will proceed step by step:
Aluminum molecular mass = $26.982$ grams.
This means that 1 mole of aluminum is equal to $26.982$ grams of aluminum.
Then, No. of moles in $9$ grams of aluminum is determined by the ratio of the mass of aluminum to the atomic mass of aluminum.
= $\dfrac{9}{{26.982}}$
Moles of aluminum = $0.333$moles
So, the No. of moles of atoms present in $9$ grams of aluminum is $0.333$moles. This refers to the fact that one third of a moles of atoms is contained in $9g$ of aluminum.
No. of atoms in 9 g of aluminum = No of moles × Avogadro number
$= 0.33 \times 6.028 \times {10^{23}}$
No. of atoms in $9g$ of aluminum
$= 2.011 \times {10^{23}}atoms$
A mole can be called as x $6.02214076 \times {10^{23}}$ of some chemical unit, be it atoms, molecules, ions, or others. The mole is a convenient unit to use because of the great number of atoms, molecules, or others in any substance.

Note:
We need to know that aluminum is a metal which belongs to group $13$ i.e. p block elements having an atomic symbol $Al$ and atomic number $13$. Aluminum has a density lower than those of other common metals, at approximately one third that of steel. Aluminum has a high chemical affinity to oxygen, which renders it suitable for use as a reducing agent.