Question

Titrul unei solutii de HCl este de 0.228 g/cm3 iar densitatea este de 1.065 g/cm3. Sa se calculeze fractia molara a substantei dizolvate. M apa=18 g/mol, M HCL=36.5 g/mol

Answer 1

T = md (g)/V(cm³) = 0,228 g/cm³
solutia de HCl :      ms    c    md = c·ms/100    Vs = ms·q
(c·ms/100) /(ms·q) = T
c/(100q) = T        c = 100·q·T = 100·1,065·0,228 = 24,282 %
X sd. = nHCl/(nHCl + nH2O)  
nHCl = c·ms / (M1·100) = 24,282·ms /(100M1)
nH2O=(100 - c)ms/(M2·100)    nHCl + nH2O =
= [M2·c·ms + M1(100 -c)ms](100M1M2) =
= (18·24,282+ 36,5·75,718)ms/(100M1·M2) =
(437,076 + 2763,707)ms /(100M1·M2) = 3200,783ms/(100M1·M2)
X HCl = 24,282ms/(100M1)· (100M1M2)/3200,783ms
x HCl = 24,282·18ms/(3200,783ms) = 0,136
 
= 18·24,282·ms + 36,5 75,718