A sample of ethane () gas has the same mass as molecules of methane (). How many molecules does the sample of gas contain?
Step 1: Finding the mass of Methane present:
molecules of methane
So,
Hence, moles
As the Molar mass of Methane:
Hence, the mass of methane:
=
Step 2: Finding the number of molecules of present in a gas sample:
Molar mass of Ethane = .
So, if the of Ethane has
Then,
= molecules
Therefore, molecules of Ethane () gas are present.