Răspuns:
Explicație:
M= 3.24 + 3.16 + 4. 28 + 8.16 + 18
=72 +48 + 112 + 128 + 18=378---------> 378g/moli
378 g --------120g MgO--------240 SiO2---------18g H2O
100 g----------------x-------------------y---------------------z
x= 100. 120 :378 =31,75 % MgO
y= 100. 240 : 378 =63,49 % SiO2
z= 100.18 : 378 =4,76 % H2O