Question

how many moles of carbon are in 33 g of C2H6

Answer 1

divide 33g by the molar mass of C2H9
Molar mass of C2H9
C is carbon and carbon's molecular weight is 12.01, but there's 2 atoms of Carbon so 12x2=24
H is hydrogen and hydrogen's molecular weight is 1.008, or 1. There's 9 atoms of Hydrogen so 1 x 9 =9

add all the MW of the elements together to get the molar mass of the compound.
24.02 + 9.072=33.092

Coindence! The gram of C2H9 we were giving is the same as the molar mass.

That must equal to 1 :)