Question

1. Calculati masa de oxid de aluminiu obtinuta prin arderea a 5 moli de aluminiu.

2. 5 moli de acid sulfuric reactioneaza cu clorura de bariu. Calculati masele produsilor de reactie.

Answer 1

1.
4Al+3O2=2Al2O3
4 moli Al...................2moli Al2O3
5moli.......................X
X=5*2/4=2,5 moli Al2O3
M Al2O3=2A Al+3AO=2*27+3*16=54+48=102g/mol
n=m/M
m=n*M=2,5*102=255 g Al2O3

2.
H2SO4+BaCl2=BaSO4+2HCl
MBaSO4=ABa+AS+4AO=137+4*16=201g/mol
MHCl=AH+ACl=1+35,5=36,5g/mol

1mol H2SO4.............201gBaS04...............2*36,5g HCl
5..............................X.............................Y
X=5*201=1005gBaSO4
Y=5*2*36,5=365 gHCl