If a propane heater burns 38.95 g c3h8, it consumes 38.95 mol c3h8. 0.8830 mol c3h8. 1 mol c3h8. 44.10 mol c3h8.

               Option-2 (0.8830 mol C₃H₈) is the correct answer.

Solution:

                 In statement we are given with the amount of propane gas and are asked to find out the moles for given mass.

As we know mass is related to moles as follow,

                                      Moles = Mass / M.mass (1)

Data Given:

                Moles = ??

                Mass = 38.95 g

                M.mass = (C)3 + (H)8 = (12)3 + (1)8 = 36 + 8 = 44 g/mol

Putting values in equation 1,

                                    Moles = 38.95 g / 44 g/mol

                                    Moles = 0.8854 Moles

the density(ratio between mass and volume as m/v) decreases from top to bottom in periodic table group as the size increases and nuclear charge decreases. but in periods density increases from left to right as atom size decreases and nuclear charge increases.