Question

A sample of C3H8 has 4.88 x 10^24 H atoms. How many carbon atoms does the sample contain? What is the total mass of the sample?

Answer 1

atomicity of H in C3H8   = 8

no of atoms   = no of moles * 6.023*10^23 * atomicity of H

4.88*10^24      = no of moles * 6.023*10^23 *8

no of moles   = 4.88*10^24/6.023*10^23 *8     = 1.013 moles

atomicity of carbon in C3H8 is 3

no of carbon atoms   = no of moles * 6.023*10^23 * atomicity of carbon

                                 = 1.013*6.023*10^23*3    = 1.83*10^24 carbon atoms

mass of C3H8   = no of moles * gram molar mass

                           = 1.013*44   = 44.572g