Question

1. Suppose you have 3.350×10²⁴ molecules of methane, CH4 .

-How many moles of methane do you have? Four sig figs

-How many grams of methane do you have?

2. How many moles of carbon atoms are there in 7 moles of propane?

Answer 1

Number of mole of CH4 = (3.35 * 10^24) / (6.023 * 10^23)

                                           = 5.562 moles

1 mole of CH4 has 16 g

then 5.562 moles of CH4 = 5.562 * 16 g

                                              = 88.992 g

1 mole of Propane contains 3 moles of Carbons

7 mole of C3H8 contains 21 mole of carbons

number of carbon atoms = 21 * 6.023 * 10^23

                                              = 1.2648 *10^25 atoms of carbon