RÄspuns:
53,33%
ExplicaČie:
SoluČia 1 are masa msā = 400g Či concentraČia cā = 10%
SoluČia 2 are masa msā = 400g Či concentraČia cā = 50%
SoluČia finalÄ (3) are masa msā Či concentraČia cā
msā = msā + msā + m(NaOH adÄugat) = 400g + 400g + 400g = 1200g
mdā = mdā + mdā + m(NaOH adÄugat)
mdā = cā Ć msā / 100 = 10 Ć 400g / 100 = 40g NaOH
mdā = cā Ć msā / 100 = 50 Ć 400g / 100 = 200g NaOH
mdā = 40g + 200g + 400g = 640g
cā = mdā Ć 100 / msā = 640g Ć 100 / 1200g = 53,33%
-Mihai