có D nước = 1g/ml
⇒ mH2O = 1.170 = 170 gam
có m dung dịch tạo thành = mCuSO4 + mNaCl + mH2O= 20+10+170 = 200 gam
có : C% CuSO4 = 20\200 .100% = 10%
C% NaCl = 10\200 .100% = 5%
\(D_{H2O}=1\left(\frac{g}{mol}\right)\)
\(\Rightarrow m_{H2O}=1.170=170\left(g\right)\)
\(m_{dd\left(tao.thanh\right)}=m_{CuSO4}+m_{NaCl}+m_{H2O}=20+10+170=200\left(g\right)\)
\(\Rightarrow\left\{{}\begin{matrix}C\%_{CuSO4}=\frac{20}{100}.100\%=10\%\\C\%_{NaCl}=\frac{10}{200}.100\%=5\%\end{matrix}\right.\)