Question

Дано.
m(NaCl+H2O)=176 г
w(NaCl)=10 ℅
m(H2O)=?
m(NaCl)=?

Answer 1

m(NaCl) = m (раствора) * w (NaCl) = 176 г * 10% /100% = 17,6 г  
m(H2O) = m(NaCl+H2O) - m(NaCl) = 176 - 17.6 = 158.4 г

Answer 2

m(NaCl) = $\frac{176 * 10}{100} = 17,6$ (г)
w(NaCl) + w($H_{2}O$) = 100%;
w($H_{2}O$) = 100% - w(NaCl) = 100% - 10% = 90%;
m($H_{2}O$) = 176 - 17,6 = 158,4 (г)