Question

how many moles of atoms are contained in 9g of aluminum

Answer 1

Moles =weight in grams /molar mass
moles of aluminium=9/26=0.34moles

Answer 2

Answer: $2.011 \times 10^{23} \ \text{atoms}$

Solution:

Aluminum molecular mass = 26.982 grams.

This refers 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.

$=\frac{9}{26.982}$

Moles of aluminum = 0.333 moles

so, the No. of moles of atoms present in 9 grams of aluminium is 0.33 moles. This refers that one third of a moles of atoms is contained in 9 g of aluminum.

No. of atoms in 9 g of aluminum = No of moles × Avogadro number

$=0.33 \times 6.022 \times 10^{23}$

No. of atoms in 9g of aluminum $=2.011 \times 10^{23} \ \text{atoms}$