Question

Reactioneaza 200 de grame de HNO3 63% cu magneziu de puritate 30%
a. Calculeaza masa de Mg folosita
b. Determina volumul de gaz degajat​

Answer 1

-calculez masa de acid din solutie

c=mdx100/ms---> md= 63x200/100g= 2x63gHNO3

-calculez moli acid, cu masa M,HNO3=63g/mol

niu=m/M= 2x63/63 mol= 2mol

-deduc moli Mg si H2 din ecuatia chimica

1mol.......2mol..................................1mol

Mg + 2HNO3---> Mg(NO3)2+ H2

x.........2mol.............................y

y= 1mol H2----> V= niuxVm= 1molx22,4l/mol= 22,4 l

x= 1mol Mg pur

-calculez masa de Mg impur ce intra in reactie

m= niuxM= 1molx24g/mol= 24g

p=m,px100/mi---> m,i=24x100/30g=.....................calculeaza !!!!!