-calculez moli H2
n(niu)= V/Vm
n= 3,36l/22,4l/mol= 0,15mol-
-din ecuatie, deduc moli oxid M2O3
M2O3 + 3H2-----> 2M + 3H2O
1mol..........3mol
x................0,15mol
x= 0,05mol oxid
-calculez masa molara a oxidului
in 5,1g oxid.....sunt 0,15mol
x..................................1mol
x=M= 102g/mol M2O3
-Calculez masa molara ,A,a metalului
102g= 2A,g+3x16gO----> A=27g/mol---> Al ---> n=3