@来山手学花 省级精品课程申报 1000g 解：xA■ 18.02gmol 55.49mol 1000g 10.0g 1802g-mo+584g-mm*2 5.49m0l+0.34m00.9939 p=p"xw=2.338kPax0.9939=2.323kPa 25.Dextran(右旋糖酐)is a polymeric carbohydrate produced by certain bacteria.It is used as a blood plasma substitute.An aqueous solution contains 0.582g of detran in 106 mLof solution at 21C.It has an osmotic pressure of 1.47mmHg.What is the average molecular weight of the dextran. 0.582g×760mmHg 解：M。=7RT=147mig1013Pax0106×8314Pa-L·m.K×294K :=6.85×10°gmol4 26.Urea ()(NH2)CO,has been used to melt ice from sidewalk because the use of salt is harmful to plants.If the saturated aqueous solution contains 44%urea by mass.What is the freezing point?(The answer will be approximate,because the equation in the text applies accurately only to dilute solution). 解：4T=1.86 K-kg.mor'×(44g÷60gmo÷0.056kg-24.4K Tr=-24.4℃ 27.The osmotic pressure of blood at 37C is 780 kPa,A solution that is given intravenously(由a静脉内)must have the same osmotic pressure as the blood.What should be the molarity(摩尔浓度即物质的量浓度)of a glucose solution to give an osmotic pressure of780 kPa at37℃. 解：=baRT 7 780kPa -R行8314kPa,LmK×310K=030ml.L 28.将12.2g苯甲酸溶于100g乙醇中，乙醇溶液沸点比乙醇升高1.20K;将12.2g苯甲 酸溶于100g苯中，沸点升高1.31K。计算苯甲酸在两种溶剂中的摩尔质量，并估计其分子状 态。已知乙醇和苯的沸点升高常数分别为120Kkgm0r和2.62 K-kgmol' 解：