Question

Calculate the number of moles for:
a) $3.0115\times {10}^{23}$ atoms of copper
b) 27.95 g of iron
c) $1.51\times {10}^{23}$ molecules of $C{O}_2$

Answer 1

a) $Numberofmoles=\frac{Numberofmolecules}{Avagadr{o}^{\prime }snumber}$

= $\frac{3.0115\times {10}^{23}}{6.023\times {10}^{23}}$ = 0.5moles.

b) 27.95 g of Iron

$Numberofmoles=\frac{Mass}{Molecularmass}$

= $\frac{27.95}{55.9}$ = 0.5moles.

c) $1.51\times {10}^{23}$ of $C{O}_2$

$Numberofmoles=\frac{Numberofmolecules}{Avagadr{o}^{\prime }snumber}$

= $\frac{1.51\times {10}^{23}}{6.023\times {10}^{23}}$ = 0.25moles.