Question

Use Avagadros number to calculate the number of molecules of H2S, the number of atoms of H, and the number of atoms of S, in 5.25 moles of H2S. Show all work and keep track of units and significant figures.

Answer 1

H2S moles = 5.25

1) calculation for H2S molecules

1 mole of H2S contain 6.023 x 10^23 molecules

         5.25 moles H2S contain howmany molecules ?

H2S molecules = 5.25 x 6.023 x 10^23

   H2S molecules      = 3.16 x 10^24

H2S -------------------------->   2 H             + S

5.25                                  2 x 5.25                     5.25

5 .25 moles H2S contain   10.5 moles H and 5.25 moles S

2) calculation for H atoms

1 mole contain --------------------------> 6.03 x 10^23 atoms

10.5 mole -------------------------------?  

H atoms = 6.023 x 10^23 x10.5

                = 6.32 x 10^24

3) calculation for S atoms

1 mole contain --------------------------> 6.03 x 10^23 atoms

5.25 mole -------------------------------?  

S atoms = 6.023 x 10^23 x 5.25

                =3.16 x 10^24