elect the correct R or S designation for the stereocenter carbon atom in the molecule. A central carbon is bonded to an isopropyl group on top, an ethyl group to the bottom right. On the left, it is also bonded to a straight propyl chain via a wedged bond and to a methyl group via a dashed bond. The stereochemistry is: R S none of the above

Mole is given as,
                                      Mole  =  mass / M.mass

M.mass of Carbon  =  12.01 g/mol

M.mass of Sulfur    =  32.06 g/mol

Solving mass for both element keeping number of moles equal to one,

For Carbon;
                              Mass  =  Mole × M.mass
 
                              Mass  =  1 mol × 12.01 g/mol

                              Mass  =  12.01 g

For Sulfur:
                              Mass  =  1 mol × 32.06 g/mol
 
                              Mass  =  32.06 g

Result:
          Hence, 1 mole of Carbon has smaller mass than 1 mole of Sulfur because the M.mass of Carbon is smaller than Sulfur due to less number of protons and neutrons in its nucleus.