Ncert Exercises & Solutions

16 g of oxygen has same number of molecules as in

1. 16 g of CO

2. 28 g of N₂

3. 14 g of N₂

4. 1.0 g of H₂

(c, d)

The number of molecules can be calculated as follows

Number of molecules

= \frac{Mass}{Molar mass} \times Avogadro number (N_{A})

Number of molecules, in 16 g oxygen

= \frac{16}{32} \times N_{A} = \frac{N_{A}}{2}

In 16 g of CO = \frac{16}{28} \times N_{A} = \frac{N_{A}}{1.75}

In 28 g of N_{2} = \frac{28}{28} \times N_{A} = N_{A}

In 14 g of N_{2} = \frac{14}{28} \times N_{A} = \frac{N_{A}}{2}

In 1 g of H_{2} = \frac{1}{2} \times N_{A} = \frac{N_{A}}{2}

So,

16 g of O_{2} = 14 g of N_{2} = 1.0 g of H_{2}