Question

What is the number of atoms in 8.5 g of NH3?

Answer 1

8.5/17 = 0.5
0.5 moles of NH3 are present.
0.5×6.022×10^23 = 3.011×10^23 molecules of NH3. Each NH3 molecule has 4 atoms. Therefore total number of atoms are 3.011×10^23 × 4 =12.044×10^23 atoms.

Answer 2

Given:

Mass of NH3 = 8.5g

To find:

The Number of atoms in 8.5g of NH3

Solution:

Number of moles = Given mass/Molar mass

Molar mass of NH3 = 14+(3x1)      (Nitrogen - 14; Hydroen- 1)  

                                = 17 g

Number of moles = 8.5/17

                             = 0.5

1 mole of atoms = 6.022 x 10^23

0.5 mole of atoms = 0.5 x 6.022 x 10^23

                               = 3.011 x 10^23 atoms

Hence, in 8.5g of NH3, there are 3.011 x 10^23 atoms.