Đáp án+ giải thích các bước làm :
a,C%dd KCl=20/600.100%=10/3%
b,PTHH:2Na +2H2O->2NaOH+H2
nNa=15/23(mol)
Theo PTHH:nNaOH=nNa=15/23(mol)
nH2=1/2nNa=1/2.15/3=15/46(mol)
mNaOH=15/23.40=26,1(g)
mH2=15/46.2=0,65(g)
mdd NaOH=15+45-0,65=59,35(g)
C%dd NaOH=26,1/59,35.100%=44%
Chúc bạn học tốt nhé!!
Em tham khảo nha :
\(\begin{array}{l}a)\\C{\% _{KCl}} = \dfrac{{20}}{{600}} \times 100\% = 3,33\% \\b)\\2Na + 2{H_2}O \to 2NaOH + {H_2}\\{n_{Na}} = \dfrac{{15}}{{23}} = 0,65mol\\{n_{{H_2}}} = \dfrac{{{n_{Na}}}}{2} = 0,325mol\\{n_{NaOH}} = {n_{Na}} = 0,65mol\\{m_{NaOH}} = 0,65 \times 40 = 26g\\C{\% _{NaOH}} = \dfrac{{26}}{{15 + 45 - 0,325 \times 2}} \times 100\% = 43,8\% \end{array}\)
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