Question

How many atoms are there in each of the following ?a.)1.50 mol Na c.) 0.250 mol. Sib.)6.755 mol Pb

Answer 1

$a) \: n = \frac{N}{NA} \\ 1.5 = \frac{x}{6.02 \times \: {10}^{23} } \\ x = 1.5 \times 6.02 \times {10}^{23} \\ x = 9.03 \times {10}^{23} \: atoms \: of \: Na$

$b) \: n = \frac{N}{NA} \\ 0.25 = \frac{x}{6.02 \times \: {10}^{23} } \\ x = 0.25 \times 6.02 \times {10}^{23} \\ x = 1.505 \times {10}^{23} \: atoms \: of \: Si \:$
$c) \: n = \frac{N}{NA} \\ 6.755 = \frac{x}{6.02 \times \: {10}^{23} } \\ x = 6.755 \times 6.02 \times {10}^{23} \\ x = 40,6651 \times {10}^{23} \\ x = 4.07 \times {10}^{24} \: atoms \: of \: Pb \:$