Question

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

Answer 1

Hint: 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.