x moli 10 moli
2 Ca + O2 = 2CaO
2moli 1mol
Se lucreaza in moli
x=2.10: 1=20 moli Ca 1mol Ca--------40g
20. 40 =800g Ca 20 moli ---------x
x=20.40=800g Ca
5,6 g xg
2 Fe +3 Cl2 =2Fe Cl3
2.56g 2.162,5g
x= 5,6 .2 .162,5 :2.56=16,25 g Fe Cl3
2g xg
Na OH + HCl= NaCl + H2O
2.40g 36,5g
Se calc. masele moleculare
MNaOH= 23+ 16 +1=40------>1mol=40g
MHCl=1 +35,5=36,5------->1mol=36,5g
x=2.36,5:40=1,8 25g HCl acesta este md
c= md.100 : ms
ms=md .100 :c
ms=1,825 .100: 10=18,25 g sol. HCl