Verified answer

а)С2Н6

W(X) = Ar(X) * a      * 100 %

             Mr вещ ва

Mr(С2Н6) = 12*2 + 1*6 = 24 + 6 = 30

w(С) = 12 * 2 / 30 = 80%

w(H) = 1 * 6 / 30 = 20%

б)С3Н8

W(X) = Ar(X) * a      * 100 %

             Mr вещ ва

Mr(С3Н8) = 12*3 + 1*8 = 44

w(С) = 12 * 3 / 44 = 82%

w(H) = 1 * 8 / 30 = 18%