基础化学习题解答.doc
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1、. .第一章1. 为什么说化学是一门中心科学?试举几例说明化学和医学的关系。解因为现代化学几乎与所有的科学和工程技术相关联,起着桥梁和纽带作用;这些科学和技术促进了化学学科的蓬勃发展,化学又反过来带动了科学和技术的进展,而且很多科技进步以化学层面的变革为突破口。因此,化学是一门中学科学。化学和医学的关系极为密切,无论是制药、生物材料、医学材料、医学检验,还是营养、卫生、疾病和环境保护,乃致对疾病、健康、器官组织结构和生命规律的认识,都离不开化学。2. SI单位制由哪几部分组成?请给出5个SI倍数单位的例子。解国际单位制由SI单位和SI单位的倍数单位组成。其中SI单位分为SI基本单位和SI导出单
2、位两大部分。SI单位的倍数单位由SI词头加SI单位构成。例如mg、nm、ps、mol、kJ等等。3. 下列数据,各包括几位有效数字?(1) 2.0321 g (2) 0.0215 L (3) pKHIn6.30 (4) 0.01 (5) 1.010-5 mol解 (1) 5位,(2) 3位,(3) 2位,(4)1位,(5)2位。4. 某物理量的真实值T = 0.1024,实验测定值X = 0.1023,测定值的相对误差RE是多少?运用公式,以百分率表示。解5. 关于渗透压力的Vant Hoff 公式写作,式中,c是物质的量浓度,R是摩尔气体常数,T是绝对温度。通过量纲分析证明渗透压力的单位是k
3、Pa。解式中,花括号代表量的值,方括号代表量的单位。6. 地球水资源是被关注的热点。有国外资料给出水资源的分布:水资源水资源体积/mi3占水资源总量百分比/%海洋317 000 00097.23,冰盖,冰川7 000 0002.15地下水2 000 0000.61淡水湖30 0000.0092已知1 mile = 1.609 344 km,把表中数据换算成SI单位数据并计算水资源的总体积。解1 mi3 = 1.609 3443 km3 = 4.168 182 km3,所以水资源的总体积V = (317 000 000 + 7 000 000 + 2 000 000 + 30 000) 4.16
4、8 182 km3 = 1.3590 109 km37. 求0.010 kg NaOH、0.100 kg (Ca2+)、0.100 kg (Na2CO3) 的物质的量。解8. 20 ,将350 g ZnCl2溶于650 g水中,溶液的体积为739.5 mL,求此溶液的物质的量浓度和质量摩尔浓度。解9. 每100 mL血浆含K+和Cl-分别为20 mg和366 mg,试计算它们的物质的量浓度,单位用mmolL-1表示。解10. 如何用含结晶水的葡萄糖(C6H12O6H2O)配制质量浓度为50.0 gL-1的葡萄糖溶液500 mL?设溶液密度为1.00 kgL-1,该溶液的物质的量浓度和葡萄糖C6
5、H12O6的摩尔分数是多少?解设称取含结晶水的葡萄糖(C6H12O6H2O)的质量为m,11. 某患者需补充Na+5.0 g,如用生理盐水补充(NaCl) = 9.0 gL-1,应需多少?解12. 溶液中KI与KMnO4反应,假如最终有0.508 g I2析出,以(KI+KMnO4)为基本单元,所消耗的反应物的物质的量是多少?解 10KI + 2KMnO4 + 8H+ = 12K+ + 2MnO2 + 5I2 + 4H2OExercises1. Which of the following is non-SI unitmilliliter, milligram, kilopascal cent
6、imeter and millimole?SolutionMilliliter is a non-SI unit.2. If you had to do the calculation of (29.837-29.24)/32.065, what would be the correct result of significant figure?Solution3. If a mole of marbles stacked tightly together, how kilometers deep would they cover the land of our country? The ra
7、dius of the marble is 1.0 cm and the area of our land is 9.6106 km2.SolutionA marble would take a hexagonal area of when stacked tightly together, and each layer of marbles would be cm deep. Therefore the deep of 1 mole of marbles covering our land would be:4. An aqueous solution is 8.50 % ammonium
8、chloride, NH4Cl, by mass. The density of the solution is 1.024 gmL-1. What are the molality, mole fraction, and amount-of-substance concentration of NH4Cl in the solution?Solution5. A 58-g sample of a gaseous fuel mixture contains 0.43 mole fraction propane, C3H8; the remainder of the mixture is but
9、ane, C4H10. What are the masses of propane and butane in the sample?Solution6. A sample of potassium aluminum sulfate 12-hydrate, KAl(SO4)212H2O, containing 118.6 mg is dissolved in 1.000 L of solution. Calculate the following for the solution:(1) The amount-of-substance concentration of KAl(SO4)2.(
10、2) The amount-of-substance concentration of SO42-.(3) The molality of KAl(SO4)2, assuming that the density of the solution is 1.00 gmL-1.Solution(1) (2) (3) 第二章1. 水在20时的饱和蒸气压为2.34 kPa 。若于100g水中溶有10.0 g蔗糖(Mr= 342),求此溶液的蒸气压。解 根据 , 2. 甲溶液由1.68 g蔗糖(Mr=342)和20.00 g水组成,乙溶液由2.45 g (Mr= 690)的某非电解质和20.00 g水组
11、成。在相同温度下,哪份溶液的蒸气压高?将两份溶液放入同一个恒温密闭的钟罩里,时间足够长,两份溶液浓度会不会发生变化,为什么?当达到系统蒸气压平衡时,转移的水的质量是多少?解 (1) 溶液乙的蒸气压下降小,故蒸气压高。(2)乙溶液浓度变浓, 甲溶液浓度变稀。因为浓度不同的溶液置于同一密闭容器中,由于不同,P不同, 蒸发与凝聚速度不同。乙溶液蒸气压高,溶剂蒸发速度大于甲溶液蒸发速度,所以溶液乙中溶剂可以转移到甲溶液。(3)设由乙溶液转移到甲溶液的水为x(g), 当两者蒸气压相等时,则x = 3.22g3.将2.80 g难挥发性物质溶于100 g水中,该溶液在101.3 kPa下,沸点为100.51
12、 。求该溶质的相对分子质量及此溶液的凝固点。(Kb = 0.512 Kkgmol-1,Kf = 1.86Kkgmol-1)解 该溶液的凝固点为-1.854.烟草有害成分尼古丁的实验式是C5H7N,今将538 mg尼古丁溶于10.0 g水,所得溶液在101.3 kPa下的沸点是100.17 。求尼古丁的分子式。解 尼古丁的分子式为: 5. 溶解3.24 g硫于40.0 g苯中,苯的凝固点降低1.62。求此溶液中硫分子是由几个硫原子组成的?(Kf = 5.10 Kkgmol-1 )解 此溶液中硫原子是由8个硫原子组成。6. 试比较下列溶液的凝固点的高低:(苯的凝固点为5.5 ,Kf = 5.12
13、Kkgmol-1,水的Kf = 1.86 Kkgmol-1) 0.1 molL-1蔗糖的水溶液; 0.1 molL-1乙二醇的水溶液; 0.1 molL-1乙二醇的苯溶液; 0.1 molL-1氯化钠水溶液。解 对于非电解质溶液,电解质溶液,故相同浓度溶液的凝固点的大小顺序是: 7. 试排出在相同温度下,下列溶液渗透压由大到小的顺序:c(C6H12O6)= 0.2 molL-1; ; ; c(NaCl)= 0.2 molL-1。解 根据非电解质溶液, 电解质溶液,渗透压大小顺序是: 8. 今有一氯化钠溶液,测得凝固点为 -0.26 ,下列说法哪个正确,为什么? 此溶液的渗透浓度为140 mmo
14、lL-1; 此溶液的渗透浓度为280 mmolL-1; 此溶液的渗透浓度为70 mmolL-1; 此溶液的渗透浓度为7 153 mmolL-1 。解 由于 NaCl 在水溶液中可以电离出2倍质点数目,该溶液的渗透浓度可认为: 所以(1)正确,氯化钠溶液的渗透浓度应为140 mmolL-19. 100 mL水溶液中含有2.00 g 白蛋白,25 时此溶液的渗透压力为0.717 kPa 求白蛋白的相对分子质量。解 10. 测得泪水的凝固点为 -0.52 ,求泪水的渗透浓度及 37 时的渗透压力。解 泪水的渗透浓度为。11.今有两种溶液,一为1.50 g 尿素(Mr = 60.05)溶于200 g
15、水中,另一为42.8 g 某非电解质溶于1000 g 水中,这两种溶液在同一温度下结冰,试求该非电解质的相对分子质量。解 若两溶液在同一温度下结冰,则 ,有 12. 在0.100kg的水中溶有0.020 mol NaCl, 0.010 mol Na2SO4和0.040 mol MgCl2。假如它们在溶液中完全电离,计算该溶液的沸点升高值。解 他们在溶液中完全电离,溶液中总质点数目为:Exercises1. What are the normal freezing points and boiling points of the following solution?(a)21.0g NaCl
16、in 135mLof water.(b) 15.4g of urea in 66.7 mL of water.Solution: (a)(b) 2. If 4.00g of a certain nonelectrolyte is dissolved in 55.0g of benzene, the resulting solution freezes at 2.36. Calculate the molecular weight of the nonelectrolyte. Solution: 3. The average osmotic pressure of seawater is abo
17、ut 30.0 atm at 25. Calculate the concentration (molarity) of an aqueous solution of urea (NH2CONH2)that is isotonic with seawater. Solution: 4. A quantity of 7.85g of a pound having the empirical formula C5H4 is dissolved 301g of benzene. The freezing point of the solution is 1.05 below that of pure
18、 benzene. What are the molar mass and molecular formula of this pound?Solution: Since the formula mass of is and the molar mass is found to be , the molecular formula of the pound is .5. Ethylene glycol (EG) CH2(OH)CH2(OH), is a mon automobile antifreeze. it is cheap, water-soluble, and fairly nonvo
19、latile (b.p.197).Calculate the freezing point of a solution containing 651g of this substance in 2505g of water. Would you keep this substance in your car radiator during the summer? The molar mass of ethylene glycol is 62.01g.Solution: M(EG)=62.01gmol-1 Because the solution will boil at 102.15,it w
20、ould be preferable to leave the antifreeze in your car radiator in summer to prevent the solution from boiling.6. A solution is prepared by dissolving 35.0g of hemoglobin (Hb) in enough water to make up one liter in volume.If the osmotic pressure of the solution is found to be 10.0mmHg at 25,calcula
21、te the molar mass of hemoglobin.Solution: the concentration of the solution:7. A 0.86 percent by mass solution of NaCl is called “physiological saline” because its osmotic pressure is equal to that of the solution in blood cell. Calculate the osmotic pressure of this solution at normal body temperat
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