Question

La oxidul de aluminiu cu masa de 5,1 g a fost adaugata o solutie ce contine acid azotic cu masa de 25,2g.Calculeaza masa sarii obtinute.

Answer 1

Al2O3 + 6 HNO3 => 2 Al(NO3)3 + 3 H2O
m Al2O3= 5.1 g
n Al2O3= 5.1 g /102(g/mol)=0.05 mol
1 mol Al2O3 consuma 6 mol HNO3 pur
0.05 mol Al2O3 consuma X mol HNO3 pur
X=6 x 0.05 = 0.3 mol HNO3 pur
m HNO3 pur = 63 g/mol x 0.3 mol = 18.9 g HNO3 pur (md)
c= 18.9/25.2 x100 = 75%
1 mol Al2O3 consuma 2 mol Al(NO3)3
0.05 mol Al2O3 consuma Y mol Al(NO3)3
Y= 0.05 x 2 = 0.1 mol Al(NO3)3
m Al(NO3)3 = 0.1 mol x 213 g/mol =21.3 g Al(NO3)3