Răspuns:
1) MMgO=24+16=40g/mol
MHCl=1+35,5=36,5g/mol
n=m/M
m=40×8=320g
40g.......2×36,5g
MgO + 2HCl => MgCl2 + H2O
320g......xg
x=320×2×36,5/40=calculează
2) MH2SO4 =2×1+32+4×16=98g/mol
1mol=98g
MCO2=12+2×16=44g/mol
1molCO2......44g
2moli.........yg
yg2×44/1=88g
MAl2O3 =2×27+3×16=102g/mol
1molAl2O3.........102g
3moli...................zg
z=3×102/1=306g
