Question

Which has more atoms, 6.0 g of silicon (Si:28) or 6.0 of iron (Fe:56)?

Answer 1

Answer:  6.0 g of silicon has more atoms

Explanation:

According to avogadro's law, 1 mole of every substance occupies 22.4 L at STP and contains avogadro's number $6.023\times 10^{23}$ of particles.

To calculate the moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text {Molar mass}}$

a) $\text{Number of moles of silicon}=\frac{6.0g}{28g/mol}=0.21moles$

1 mole of Si contains = $6.023\times 10^{23}$ atoms

0.21 moles of Si contains = $\frac{6.023\times 10^{23}}{1}\times 0.21=1.26\times 10^{23}$ atoms

b) $\text{Number of moles of iron}=\frac{6.0g}{56g/mol}=0.11moles$

1 mole of Fe contains = $6.023\times 10^{23}$ atoms

0.11 moles of Fe contains = $\frac{6.023\times 10^{23}}{1}\times 0.11=0.66\times 10^{23}$ atoms

Thus 6.0 g of silicon has more atoms