NaCl
23g Na........35,5g Cl.........58,5g NaCl
x.....................y.......................100g NaCl
y = 35,5*100/58,5 = 60,68% Cl
x = 100 - 60,68 = 39,32% Na
Al2(SO4)3
54g Al........96g S........192g O.......342g Al2(SO4)3
x.................y...................z................100g Al2(SO4)3
x = 54*100/342 = 15,79% Al
y = 96*100/342 = 28,07% S
z = 100 - 15,79 - 28,07 = 56,14% O