A sample of C3H8 has 3.28 × 1024 H atoms. How many carbon atoms does the sample contain? What is the total mass of the sample in grams?

Question

anonymous · Answer

It should be 3.28 X 10^24

From this find the moles of Hydrogen by applying this formula.
moles = no. of atoms/ Avogadro's no (NA)
moles = 5.446
then use the ratio of Carbon and Hydrogen from the formula:
      C   =     H
      3    =     8
      3/8 * 5.466 = 5.466
2.05 moles of C.
now: no of C atoms = moles X NA
                                    = 2.05 X 6.022 X 10^23 = 1.27 X10^24


2nd Part:
One mole of C3H8 = 3 moles of C
     1/3 * 2.05           =  2.05 moles of C
0.68 moles of C3H8.

mass of C3H8 = moles X molar mass
mass of C3H8 = 0.68 X 44 = 30.2 grams of C3H8