Question

Ce cantitate de hidrogen se gaseste in 68 g H2S ?

Answer 1

MH2S = 2AH + AS = 2*1+32=34g/mol

mH=2*1=2g

34g H2S..........................2g H
68g H2S..........................x=4gH

Answer 2

$H_{2}$S este acidul sulhidric
$m_{H2S}$=68g
$M_{H2S}$= 2*1+1*32 = 2+32-34
1 mol acid sulhidric = 34 g 
In 34 g $H_{2} S$---------- 2g H
In 68 g ---------- x g H

$\frac{34}{68}$=$\frac{2}{x}$ 
x=$\frac{2*68}{34}$ = 4 g H