A hydrcarbon y contains 85.75% carbon and has a density of 2.5g/l at stp
a) Calculate the empirical formula of y
b) Determine the molecular formular of y
c) Write the structural formulae of the possible chain isomers of y
d) ozonolysis of y and subsequent work-up gave one compound. identify y
e)write an equation to show how y can be synthesized from butan-2-ol and indicate a mchanism for the reaction
a.
Take a 100 g sample. That gives you 85.75 g C and 14.25 g H.
moles C = 85.75/12.01 = 7.14
moles H = 14.25/1.008 = 14.14
Find the ratio of the two with the smallest subscript being 1.0. To do this just divide both numbers by the smaller of the two like this:
moles C = 7.14/7.14 = 1.00
mols H = 14.14/7.14 = 1.98 which rounds to 2.0
To the empirical formula is CH2 with an empirical mass of 12 + 2 = 14.
b.
If the density is 2.5 g/L then 1 mole, which will occupy 22.4 L @ STP, will have a mass of 2.5 x 22.4 = 56. Therefore, the molar mass is 56 and the empirical mass is 14, there must be 56/14 = 4 so the molecular formula is (CH2)4 or C4H8.
c,d,e. Can't draw structures on this web site. You can google and find the isomers and look up the ozonolysis products; thus you can determine which isomer is present for compound y; i.e., which isomer identifies y.