ms= 11,7 kg , c%= 80%
c% = mdx100/ms => md = msxc%/100
= 11,7x80/100 = 9,36 kg NaCl
M.NaCl = 58,5 kg/kmol
=> 9,36/58,8 = 0,16 kmoli NaCl
1 kmol NaCl ...... 6,022x10la23 ioni de Na+ si de Cl-
0,16 kmoli ........ a = 9,64x10la22 ioni Na+ si Cl-
b)
ms.final = ms + m.apa = 31,7 kg
=> c%.final = mdx100/ms.final
= 9,36x100/31,7 = 3,04%