m р-ра=250 г
w=15%
w=15%:100%=0,15
m вещ-ва=0,15*250=37,5 г-масса растворённого вещ-ва
Масса осадка может быть разной при использовании разных реактивов
Mg3N2=3Mg+N2;
N2+3H2=2NH3;
2NH3+H2SO4=(NH4)2SO4;
<span>CuO + C= Cu + CO
</span><span>Cu+Hg(NO3)2=Cu(NO3)2 + Hg
</span>CuO+CO=Cu+CO<span>2
</span><span>CuO+H2So4=CuSO4+H2O
</span><span>CuO+H2=Cu+H2O
</span><span>Mg+CuO=MgO+Cu
</span>C2H5OH+CuO=CH3COH+Cu+H2O
<span>2Cu+O2=2CuO
</span><span>Cu(OH)2=CuO+H2O
</span>Cu2(OH)2CO3=<span>2CuO + CO2 + H2O
</span><span>CU(OH)2+2HCl=CuCl2+2H2O
</span>2Cu(OH)2+CO2=<span>Cu2(OH)2CO3+H2O
</span><span>CH3COH+2CU(OH)2=CH3COOH+Cu2O+2
H2O
</span><span>CuSO4+2NaOH=Cu(OH)2+Na2SO4</span>
C6H6Br+NaOh=C6H5OH+NaBr
C6H5OH+3Br2=C6H2(OH)(Br3)+3HBr
<span>а) Mg + 2HBr --> </span>Mg<span>Br2+ 2H
б)</span><span> Li2O + H2SO4 --></span>Li<span>2SO4+ H2O
</span>BaO + 2HNO3 -->Ba(NO3)2+H2O
Fe(OH)2 + 2HNO3 -->Fe(NO3 )2 +H2O
<span>2HaOH + H2S -->Ha2S+2H2O
</span>K2SiO3 + H3PO4<span>-->K3PO4+H2S+H2O
</span>