alcanul are formula generala CnH2n+2 si masa molara M= 12n+2n+2
in (14n+2g) alcan sunt.....(2n+2) gH
si 100g..............................17,24g
100(2n+2)= 17,24(14n+2)-----> n= 4--> butan
CH3-CH2-CH2-CH3 -----> CH2=CH-CH2-CH3 SAU
CH3-CH=CH-CH3 SUNT 2 BUTENE--->
formula restransa este C4H8......>verifica daca m,C/m,H= 6/1 ......!!!!!!!!!!