<span>3CaBr2 + 2Al = 3Ca + 2AlBr<span>3
</span></span><span>2Ca + O2 = 2CaO
</span><span>CaO + H2O = Ca(OH)<span>2
</span></span><span>Ca(OH)2 + CO2 = CaCO3 + H2O
</span><span>CaCO3 + H2SO4 = CaSO4 + CO2 + H2O</span>
А) 2Mg + O2 = 2MgOMgO + H2SO4 = MgSO4 + H2OMgSO4 + BaCl2 = BaSO4 + MgCl2
Б) S + O2 = SO22SO2 + O2 = 2SO3SO3 + 2NaOH = Na2SO4 + H2ONa2SO4 + Ba(NO3)2 = BaSO4 + 2NaNO3
HgO+H2=Hg+H2O
коэффициенты сам расставишь
M = n*M
M(<span>H3PO4) = 98 г\моль
m= 2.5 моль * 98 г\моль = 245 г</span>