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Report Sheet Colligative Properties: Freezing Point Depression and Molar Mass If

ID: 810386 • Letter: R

Question


Report Sheet Colligative Properties: Freezing Point Depression and Molar Mass If the freezing point of the solution had been incorrectly read 0.3 degree lower than the true freezing point, would the calculated molar mass of the solute have been too high or too low? Explain your answer. Arrange the following aqueous solutions in order of increasing freezing points (lowest to highest temperature): 0.10 m glucose, 0.10 m BaCl2, 0.20 m NaCl, and 0.20 m Na2SO4. What mass of NaCl is dissolved in 200 g of water in a 0.100 m solution?

Explanation / Answer

4) molar mass low. Colligative property inversly proportional to molar mass but freezing point is reverse to CP. Freezing point decreses means molar mass also decrese.

5) freezing point inversily proportional to molality

So .

0.1m glucose > 0.1mBaCl2 > 0.2m NaCl > 0.2m Na2SO4

6) molalit = moles x1000/wt of solvent

0.1= w x 1000/18 x200

weight= 0.9gm