<span>P2O5 + 6KOH = 2K3PO4 + 3H2O</span>
а-2
Ca +2 NaOH=Ca(OH)2+2Na
<span>Ca + 2H2O=Ca(OH)2 +H2</span>
<span>2Ca+O2=2CaOб</span>
б-3
<span><span>KOH +NH4Cl=KCl+NH3+H2O</span></span>
<span><span><span>6KOH +P2O5=2K3PO4+3H2O</span></span></span>
<span><span><span><span>2KOH +CrO3=<span>K2CrO3+Н2O</span></span></span></span></span>
<span><span><span><span><span>в-2</span></span></span></span></span>
<span><span><span><span><span><span>SO2 +2NaOH=Na2SO3+H2O</span></span></span></span></span></span>
<span><span><span><span><span><span><span>SO2 +H2O=H2SO3</span></span></span></span></span></span></span>
<span>SO2 +O2=2SO3</span>
<span>г-5</span>
<span><span><span> ZnS + O2 = Zn+SO2</span></span></span>
<span><span><span><span> ZnS +2HСl=ZnСl2+H2S(газ)</span></span></span></span>
<span><span><span><span><span> ZnS + 2HNO3=Zn(NO3)2+H2S(газ)</span></span></span></span></span>
3412 эту последовательность цифр и надо записать в ответе
Дано:m(BaСl2)=250гр
w(BaCl2)=8%
m(осадка)-?
Решение:BaCl2 + H2SO4 = BaSO4↓ + 2HCl
m(чистого BaCl2)=250гр*8%/100=20г
n(BaCl2)=m/M=20гр/208гр/моль=0,1 моль примерно
n(BaCl2)=n(BaSO4)=0,1 моль
m(BaSO4)=n*M=233г/моль*0,1 моль=23,3гр
BaCl2 + H2SO4 = BaSO4 + 2HCl
n(BaSO4)= m(BaSO4) /M(BaSO4) = 699г/233г/моль = 3 моль
По уравнению реакции n(BaSO4) =n(H2SO4) = 3 моль