formula dioxidului de sulf = SO2
M moleculara = 1 x As + 2 xAo = 1 x32 + 2x16 = 64 g/mol
daca la 64 g SO2 ............avem...... 32 g S
..... la 100 % SO2 ..... vom avea..... a% S => a = 32 x 100 / 64
=> a = 50% S