a) Se calculeaza masa molara a compusului: M=12*8+1*10=106
106 g C8H10......12*8 g C......1*10 g H
100 g C8H10.......x.....................y
x=90,56% C
y=9,43 % H
b) M=7*12+1*14=98
98 g C7H14..........7*12 g C...............1*14 g H
100 g C7H14...............x.....................y
x=85,71% C
y=14,28 % H
