If you have 5 moles of c3h8 and 5 moles of c4h10, which sample has more molecules? which sample has more mass?

The mass of butane is more than the mass of propane and both the compounds have same number of molecules.

Explanation:

We are given:

Moles of propane = 5 moles

Moles of butane = 5 moles

According to mole concept:

1 mole of a compound contains number of molecules

So, 5 moles of propane will contain = number of molecules.

And, 5 moles of butane will contain = number of molecules.

To calculate the mass for given number of moles, we use the equation:

    .....(1)

Moles of propane = 5 moles

Molar mass of propane  = 44 g/mol

Putting values in equation 1, we get:

Moles of butane = 5 moles

Molar mass of butane = 58 g/mol

Putting values in equation 1, we get:

Mass of butane > Mass of propane

Hence, the mass of butane is more than the mass of propane and both the compounds have same number of molecules.