Question

How many moles of atoms are in each elemental sample?

(a) 4.6 X 1024 Pb atoms
(b) 2.87 × 10- He atoms
(c) 7.91 × 102 K atoms
(d) 4.41 × 10- Ca atoms

Answer 1

To convert the number of atoms to moles, we can use Avogadro's number, which is approximately 6.022 x 10^23 atoms per mole.

(a) For 4.6 x 10^24 Pb atoms, the number of moles is: 4.6 x 10^24 Pb atoms / 6.022 x 10^23 atoms/mol = 0.764 mol Pb

(b) For 2.87 x 10^-2 He atoms, the number of moles is: 2.87 x 10^-2 He atoms / 6.022 x 10^23 atoms/mol = 4.77 x 10^-26 mol He

(c) For 7.91 x 10^2 K atoms, the number of moles is: 7.91 x 10^2 K atoms / 6.022 x 10^23 atoms/mol = 1.31 x 10^-21 mol K

(d) For 4.41 x 10^-2 Ca atoms, the number of moles is: 4.41 x 10^-2 Ca atoms / 6.022 x 10^23 atoms/mol = 7.30 x 10^-26 mol Ca