ta có: mdd = mdm +mct
=> mdd = 13,1 +50 = 63,1g
C% = \(\frac{m_{ct}}{m_d_d}.100\%\)
=\(\frac{13,1}{63,1}.100\%\)
= 20,8%
\(C\%_{ddNa_2O}=\frac{m_{ct}}{m_{dd}}.100\%=\frac{13,1}{\left(13,1+50\right)}.100\%\approx20,8\left(\%\right)\)
mdd = 13,1 + 50 = 63,1 (g)
\(C\%=\frac{13,1}{62,1}.100\%=20,76\%\)
Ta có \(m_{dd}=m_{ct}+m_{dm}\Rightarrow m_{dd}=13,1+50=63,1\left(g\right)\)
\(\Rightarrow C\%=\frac{m_{ct}}{m_{dd}}.100\%=\frac{13,1}{63,1}.100\%=20,76\%\)
khối lượng dd thu được là:
mdd= mNA2O +mH20= 13,1 +50=63,1g
=) C% NA20= mNA2O/mdd= 13,1/63,1%~ 20,76%