1. %Cr=100-31,6=68,4
Cr=68,4/52=1,315 => 1 atom
=> Formula bruta (CrO1,5)
O=31,6/16=1,975 => 1,5 atomi
pentru n=2 => Cr2O3 - oxid de crom
2. n=m/M=0,07/28=0.0025kmoli=2,5 moli N2
1 atm=101,325 Pa
142/101,325=1,4 atm ?..
pV=nRT=
Mg...............................22,4L
3. M + 2H2O = M(OH)2 + H2
6,85g.............................1,12L
1,12M=153,44=>M=137 => Metalul corespunzator este Ba=137