Asample of c3h8 has 6.96 × 1024 h atoms. how many carbon atoms does the sample contain?

A sample has 3.28 X 10^24 h atoms
 
 so first we will find the moles of Hydrogen by putting values in formula 
that is
. moles = no. of atoms/ Avogadro's no (NA) moles
 = 5.446 we got this
 now the ratio of Carbon and Hydrogen is: C = H 
      3 = 8 
now multiply it with the moles
      3/8 * 5.466 = 5.466 2.05 is the moles of C
. now:find the no of C atoms by this
 = moles X NA 
 = 2.05 X 6.022 X 10^23
 = 1.27 X10^2
now will find the mass of sampl:
  so One mole of C3H8 = 3 moles of C 1/3 * 2.05 = 2.05 moles of C
 0.68 moles of C3H8. 
 now the mass of C3H8 = moles X molar mass mass of C3H8
 which is = 0.68 X 44 =
 30.2 grams of C3H8

They are all full and don't need any more electrons in there outer shell.