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Which has a greater boiling point elevation and which will have a small freezing point depression?
Question
Which has the greater boiling point elevation: 3 g Ca(NO3)2 in 60 g water or 6 g Ca(NO3)2 in 30 g water?
Which will have a small freezing point depression: 100 g of methanol (CH3OH) in 500 g of water or 200 g of methanol in 250 g of water?
Answer:
Moles Ca(NO3)2 = 3 / 164 g/mol =0.018
molality = 0.018 mol / 0.060 Kg = 0.3
Ca(NO3)2 >> Ca2+ + NO32- => i = 3
delta T = i x kb x m = 3 x 0.512 x...
Calculate Vapor Pressure Depression Glucose and CaCl2 Solutions
Question
A. 10.0 g sample of the solid sucrose ( sugar, C12H22O11) was dissolved in 200.0 g of water. What will the vapor pressure of this solution be at 25C, if the normal vapor pressure of pure water at 25C is 23.8 torr?
B. Predict the vapor pressure of a solution prepared by dissolving 49.4 g of solid calcium chloride, CaCl, in150 g of water at 25C. The vapor pressure of water at 25C is 23.8 torr.
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Mencari Berat Molekul Suatu Senyawa Dengan Menggunakan Titik Beku Larutan
Titik beku bensena C6H6 murni adalah 5.48 C, apabila 20 gram suatu senyawa dilarutkan dlam 500 gram bensena maka titik beku larutan sekarang menjadi 3.77 C. Berrapakah berat molekul zat tersebut jika diketahui Kf bensena 5.12 C/m?
Jawab:
Perubahan titik bekunya adalah,
^Tf = 5.48 – 3.77 = 1.71 C
karena
^Tf = m x Kf
m = ^Tf/Kf = 1.71 / 5.12 = 0.333984375 molal
kita tahu bahwa molalitas adalah...
Boiling Point Elevation and Freezing Point Depression Question?
Question
Calculate the boiling point and freezing point of the following. 3m of sugar water, 3m of Lithium nitrate, 3m of lead (II) chlorate and 3m of ammonium phsphate.
Answer:
When a solute is dissolved in a solvent, the freezing point of a solution is lowered according to the equation:
^Tf = i•Kf•m
and the boiling point of a solution is elevated according to the equation:
^T = i•Kb•m
where;
^Tb...
Menghitung Titik Beku Larutan Gula, LiNO3, Pb(CLO3)2, dan (NH4)3PO4
Soal
Berapakah titik didih dan titik beku larutan 3 m gula, 3 m LiNO3, 3 m Pb(ClO3)2, dan 3 m (NH4)3PO4?
Jawab:
Apabila terdapat zat terlarut di dalam suatu larutan maka titik beku larutan akan turun sesuai dengan persamaan berikut ini:
^Tf = m.Kf.i
dimana i adalah faktor Van Hoff yaitu menyatakan berapa banyak zat terlarut membentuk ion dalam larutan.
Pengukuran titik beku
3 m Gula C12H22O11, gula...
Mencari Titik Didih Larutan Urea
Berapakah titik didih larutan 19 gram urea CO(NH2)2 dalam 80 gram air? jika diketahui Kb air 0.512 C/m?
Jawab:
Untuk menjawab soal diatas maka kita terlebih dahulu mencari mol dari urea tersbut,
mol urea = massa/Mr = 19/60.06 = 0.316 mol
massa air = 80 gram = 0.08 Kg
molalitas larutan dapat dicari dengan menggunakan rumus berikut ini:
m urea = mol urea/Kg air = 0.316 / 0.08 = 3.95 molal
maka perubahan...
