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