y Chapter 12-Google Chrome 0 https://session.masteringchemistry.com/myct/itemVie

Question

y Chapter 12-Google Chrome 0 https://session.masteringchemistry.com/myct/itemView?assignmentProblemID-587432248koffset-ne CHEM-132-02 For Spring 2016 Chapler 12 Item 14 Calculate the treezing point and boiling point of each aqueous soluton, assuming complete dissociation of the solute. Part A Calculate the treezing point of the solution containing 0.106 m KS Submit My Answers Give Up Part B Calculate the boiling point of the solution above Submit My Answers Give Up Part C Calculate the teezing point of the solution containing 25.5 g of CuCla in 459 g water Submt My Answers Give U

Explanation / Answer

Answer:

Part A)

delta T = m x i x kf
K2S àà 2 K+ + S2- àà3 ions-----------------Complete dissociation

i = 3

kf= 1.86, m=molality, substituting values in equation,
delta T = 0.106 x 3 x 1.86 = 0.591
Freezing point = 0 - 0.591 = - 0.591 °C

Part B)in the same way
delta T = 0.106 x 3 x 0.512 = 0.162---------( The Kb constant for water is .512 deg.C/m)

Boiling point = 100 + 0.162 = 100.162°C

Part C) Moles CuCl2 = 25.5 g / 134.452 g/mol= 0.189
m = 0.160 moles of CuCl2/ 0.450 Kg of water = 0.355
also in this case i = 3 ( CuCl2ààCu2+   + 2Cl-)
delta T = 0.356 x 3 x 1.86 = 1.984
Freezing point = 0-1.984= - 1.984 °C
delta T = 0.355 x 3 x 0.512 = 0.545
Boiling point = 100.545 °C

Related Questions

Navigate

• Browse (All)
• Browse Y
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.