Question

Answer rrrrrrrrr....

Answer 1

Answer:

The answer is "Option b".

Explanation:

$\to \text{number of moles} = \frac{\text{number of atoms}}{\text{avogadro number}}$

                               $= \frac{7.0 \times 10^{19}}{6.0221 \times 10^{23}}\\\\= 1.16 \times 10^{-4} \ moles\\\\ =1.2 \times 10^{-4} \ moles$

$\to \text{sample mass}= \text{number of moles} \times \text{molar mass}$

                        $=1.16 \times 10^{-4}\times 58.9\\\\=0.00685 \\\\ = 6.85\ g$