Question

The total number of atoms in 8.5g of NH₃

• A. 9.033 X 10²³
• B. 3.011 X 10²³
• C. 1.2044 X 10²³
• D. None of these

Answer 1

The correct option is B

3.011 X 10²³

The explanation for the correct option

(B) 3.011 X 10²³ atoms

• The gram atomic mass(GAM) of NH₃ is 17g ( mass of N=14, H=1)
• One mole of Ammonia contains one GAM of ammonia, 17gm, given mass = 8.5g
• $$\begin{gathered} No.ofmoles=\frac{Givenmass}{GAM} \\ =\frac{8.5}{17}=0.5mole \end{gathered}$$
• 1 mole = 6.022 X 10²³ atoms( 1mole contains 6.022 X 10²³ atoms)
• So, in 0.5mole
• $$\begin{gathered} 0.5mole=\frac{6.022X{10}^{23}}{2} \\ =3.011X{10}^{23}atoms \end{gathered}$$

Thus option (B), is correct 8.5g of NH₃ contains 3.011 X 10²³ atoms