Number of moles is defined as the ratio of given mass in g to the molar mass.
The mathematical formula is:
Number of moles = [tex]\frac{given mass in g}{molar mass}[/tex] (1)
Number of zinc atoms is equal to [tex]1.7\times10^{23}[/tex], by Avogadro number, number of moles can be calculated.
As, 1 mol=[tex]6.022\times10^{23}[/tex] atoms, hence,
[tex]1.7\times10^{23}\times\frac{1 mol}{6.022\times10^{23} }[/tex]
= 0.2822 mol
Now, from formula (1), calculate mass in g (molar mass of zinc = 65.4 g/mol)
0.2822 mol = [tex]\frac{mass in g}{65.4 g/mol}[/tex]
mass in g = [tex]{0.2822 mol \times 65.4 g/mol[/tex]
= 18.45588 g
Thus, by rounding off the above number, it will come near about 19 g approximately.
Hence, option (C) is the correct answer.
