Question

How many silver (Ag) atoms are in a silver bar that is 20.0 g? A. 1.3 3 1027 Ag atoms B. 6.02 3 1023 Ag atoms C. 1.1 3 1023 Ag atoms D. 1.8 3 1023 Ag atoms

Answer 1

C. 1.1 3 1023 Ag atoms

Answer 2

Answer: The correct option is, (C) $1.13\times 10^{23}$

Explanation: Given,

Mass of Ag = 20 g

Molar mass of Ag = 108 g/mole

First we have to calculate the moles of Ag.

$\text{Moles of }Ag=\frac{\text{Mass of }Ag}{\text{Molar mass of }Ag}=\frac{20g}{108g/mole}=0.185moles$

Now we have to calculate the number of atoms in Ag.

As, 1 mole of Ag contains $6.022\times 10^{23}$ number of Ag atoms

So, 0.185 mole of Ag contains $0.185\times 6.022\times 10^{23}=1.13\times 10^{23}$ number of Ag atoms

Therefore, the number of atoms present in Ag are, $1.13\times 10^{23}$