M,SiH4=32g/mol
M,H2SO4= 98g/mol
-calculez masa de hidrogen din masa data de SiH4
32g SiH4...........4gH
6,4g....................0,8g H
-calculez masa de H2SO4 care contine o,8gH
98g H2SO4...........2gH
X............................0,8g
x=0,8x98/2 gH2SO4=.........................CALCULEAZA !!!