Mr CnH2n+1Br = Ar Br/ w Br*100% = 80/65%*100% = 80/0,65 = 123
СnH2n+1 = 123-80; 12n+2n+1 = 43; 14n+1 = 43; 14n = 42; n = 3; 2n+1 = 7; формула вещества = С3Н7Br
