Răspuns:
1.
MgO+2HCl→MgCl2+H2O
2Li+2HNO3→2LiNO3+H2
2Na+2H2O→2NaOH+H2
3Ca(OH)2+H3PO4→Ca3(PO4)2+6H2O
2.
p=m,purx100/m,inpur----> m,p= 8x80/100g= 6,4gMg pur
A,Mg= 24g/mol
M,MgO= (24+16)g/mol= 40g/mol
2x24g 2x40g
2Mg + O2 → 2MgO
6,4g x g
x=m=6,4x40/24g=10,66gMgO
Explicație: