Răspuns:
calculez masa de Mg pur din 30g Mg impur,de puritate 96%
p=m,px100/m,i---> m,p= 30x96/100g= 28,8g
calculez moli Mg, stiind A,Mg-=24g/mol
niu= m/A= 28,8/24mol= 1,2molMg
-calculez moli si masa oxid de magneziu din ecuatia chimica
2mol..........................2mol
2Mg + O2---> 2MgO
1,2mol....................s
x= niu=1,2molMgO
miuMgO= 40g/mol
m= niuxmiu=1,2x40g=48gMgO
Explicație:
