2Mg + O2 = 2MgO
<span>MgO + H2O = Mg(OH)<span>2
</span></span><span>Mg(OH)2 + 2HCl = MgCl2 + 2H2O
</span><span>
</span>FeCl2+2KOH <span>= Fe(OH)2 </span>+ 2KCl<span>
2Fe(OH)3 = Fe2O3 + 3H2O</span>
<span>
MgCO3 + 2HCl = MgCl2 + CO<span>2 </span> + H2O</span>
<span>CuCl2 + Fe = FeCl2 + Cu</span>
Азот.к-та пассивирует с Al,Fe,Cr
4HNO3+CU=Cu(NO3)2+2NO2+2H20
4HNO3+Mg=Mg(NO3)2+2NO2+2H2O
Ag+2HNO3=AgNO3+NO2+H2O
СH4 + 2O2 = CO2 + 2H2O
CO2 + CaO = CaCO3
CaCO3 + CO2 + H2O = Ca(HCO3)2
Ca(HCO3)2 + 2HCl = 2CO2 + 2H2O + CaCl2
CO2 + C = 2CO
40,5 -----х
65,37 ------ 98
х= 60,7
(60,7/245)*100% = 24,782% или правильней 25%.Удачи!