Pb -> PbO -> PbSO4 -> Pb(OH)2 -> PbO -> Pb -> PbCl2.
1. 2Pb+O2=2PbO
2.Pb+ Н2SO4=Н2O+PbSO4
3.PbSO4+2NaOН=Na2SO4+Pb(OH)2 выпадает в осадок
4. Pb(OH)2= PbО+Н2O
5.PbО+Н2=Pb+ Н2О
6. Pb+MgCl= PbCl2+Mg
1. <span>В)</span>
2. В)
3. А) 4P+5O2=2P2O5, Б) <em>CaCO3</em><span>+</span><em>2HNO3</em><span>=</span><em>Ca</em><span>(</span><em>NO3</em><span>)</span><em>2</em><span>+H2O+</span><em>CO2</em><span>.</span>
4. 2Na+Cl2=2NaCl; <span>NaOH + HCl = <span> NaCl + H2O; <span>2NaO + 2HCl</span><span> = 2NaCl + H2O. </span></span></span>
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Al2O3
w(O)=M(O)*3/M(Al2O3)*100%=16*3/(27*2+16*3)*100%=48/102*100%=47.05%