un alcan are formula generala CnH2n+2
prin arderea unui mol, rezulta n,Co2------->
1,45g alcan............2,24/22,4lCo2
14n+2 g..........................n ,CO2
1,45n= 0,1(14n+2).....................> calculeaza n si afli alcanul,inlocuind in formula generala !