Question

No of moles in 51g of alluminium

Answer 1

mass of Al is 27

so, no. of moles=given mass/molar mass=51/27=17/9=1.88

Answer 2

$\bullet \: \sf \green{Number \: of \: moles = \frac{Given \: mass}{Atomic \: mass} }$

$\longrightarrow \sf {Number \: of \: moles = \cancel\frac{51}{27} }$

$\therefore \sf {Number \: of \: moles = 1.89}$