Question

Superscript 15
How many moles of Pb is 9.3 X 1015 atoms of pb?


1 mol of Pb atoms will contain 6.02 x 10^23 atoms of Pb.
So 9.3 x 10^15 atoms x (1 mol/6.02 x 10^23 atoms) = ?

note how the unit "atoms" cancel leaving mol and that is the unit we want.

thanks What is the molar mass of ethane, C2H6?

C'mon now. (2*12)+(6*1)=??

thanks..alot