Массовая доля = m в-ва/m смеси (или р-ра);
m Ca(NO3)2 в исх. р-ре = 75*0.02 = 1.5 г;
<span>
в x г Ca(NO3)2*4H2O сод-я (x/236)*164 = 0.6949*x г Ca(NO3)2;
</span>тогда 1.5+0.6949*x/(75+x) = 0.14, откуда <span><span>x = 16.22 г.</span></span>
S + O2 = SO2
1 моль + 1 моль = 1 моль
<span>nS = 4/32 = 0,125 моль </span>
nS = nО
nО = 0,125 моль
<span>VO = 0,125*22,4 = 2,8 л </span>
Vвозд. = 2,8*100/20 = 14 л
<span>P.S. Кислорода в воздухе 21% по объему. </span>
решено правильно. у нас реагирует <span>N2O5 с H2O и получается 2HNO3</span>
1 (C6H10O5)n+nH2O=nC6H12O6 (катализатор H2SO4)
<span>Fe2(SO4)</span><em>3+<span> KOH=<span>2Fe(OH)3+3K2SO4</span></span></em>
<em><span><span><span><em>MgO+Sr(OH)2=</em></span></span></span></em>
<em><span><span><span><em /><span>CO2+<span> NaOH=<span>NaHCO3</span></span></span></span></span></span></em>
<em>K2O+H2O=<span>2КОН</span></em>
<em><span><span>P4O10+Са(OH)2=<span>2Са3(РО4)2 + 6Н2О</span></span></span></em>
<em><span><span><span><span>2Al + 6HCl(разб.) = 2AlCl3 + 3H2↑</span></span></span></span></em>
<em>H2CO3+Ba(OH)2=<span>BaCO3 + 2H2O</span></em>
<em><span><span>MgSO4+<span> Са(NО3)2=</span></span></span></em>
<em>zn+<span>Pb (NO3)2=<span>Pb + Zn(NO3)2</span></span></em>
<em><span><span><em>LiOH</em><span> + </span><em>NiO</em><span> = LiO + NiOH</span></span></span></em>
<em><span><span><span>Hg+<span>HBr=</span></span></span></span></em>
<em><span><span>mgO=Mg+O</span></span></em>
