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

`7.528xx10^(22)`

Explanation

In 1 gram of the mixture 0.2g of hydrogen and 0.6g of oxygen are present. Moles of `H_(2)=(0.2)/(2)=0.1`. Moles of oxygen `=(0.8)/(32)=0.025`. Calculate the number of molecules of hydrogen and oxygen and then add.