Question

A mixture of hydrogen and oxygen contains 20% by mass of hydrogen. What is the total number of molecules present per gram of the mixture?

Answer 1

In 1 gram of the mixture, 0.2 g of hydrogen and 0.8 g of 2. oxygen are present. Moles of $H_2=\frac{0.2}{2}=0.I$, moles of oxygen $\frac{0.8}{32}=0.025$. Calculate the number of molecules of hydrogen 32 and oxygen and then add.

Hence, answer will be $7.528\times {10}^{22}$.