60 likes | 188 Views
CHEM 433 - 11/ 16/11. VI. Mixtures: • Colligative Properties (5.5) Osmotic Pressure • Thermodynamic Description of Ionic Solutions ( 5.9 and beyond ) - mix G ° (i.e. what does it mean?) - mix G IDEAL (i.e. w / composition dependence) - mix G REAL ( w / activities)
E N D
CHEM 433 - 11/16/11 VI. Mixtures: • Colligative Properties (5.5) Osmotic Pressure • Thermodynamic Description of Ionic Solutions (5.9 and beyond) - mixG° (i.e. what does it mean?) - mixGIDEAL(i.e. w/ composition dependence) - mixGREAL(w/ activities) READ: CHAPTER 5 EXAM W/ Review T: web almost up to date ..
NaCl (s) —> Na+(g) + Cl– (g) LATH = +787 kJ Na+(g) + Cl– (g) —> Na+(aq) + Cl– (aq) HYDH = -784 kJ Net : SOLNH = + 3 kJ/mol Entropy must be driving force …
fH°, Sm°, and fG° for ions: H+ is benchmark .. All set to 0 for H+(aq) (1 M, 1 bar) Note for Al+3: fH° = -531 kJ/mol (! – why ?) Sm° = -321.7 J/Kmol (huh – why ?)