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1、第7章 化学动力学1以氨的分解反应2NH3= N23H2为例，导出反应进度的增加速率与， 之间的关系，并说明何者用于反应速率时与选择哪种物质为准无关。解：，2甲醇的合成反应如下：CO22 = CH3OH已知，求，各为多少?（答案：2.44，4.88moldm-3h-1）解：，3下列复杂反应由所示若干简单反应组成，试根据质量作用定律写出以各物质为准的速率方程式。(1) (2) (3) (4) 解：(1) ，(2) (3) (4) 4理想气体反应 2N2O5 4NO2O2，在298.15 K的速率常数k是1.7310-5-1，速率方程为。(1)计算在298.15K、12.0 dm3的容器中，此反应
2、的和即各为多少?(2)计算在(1)的反应条件下，1s内被分解的N2O5分子数目。（答案：（1）7.110-8，-1.1410-7mddm-3s-1 （2）1.011018）解：（1） moldm-3moldm-3s-1moldm-3s-1（2）1.410-712.06.0221023=1.011018个分子5已知每克陨石中含238U 6.310-8，He为20.7710st1:chmetcnv UnitName=cm SourceValue=6 HasSpace=False Negative=True NumberType=1 TCSC=0-6cm3(标准状态下)，238U的衰变为一级反应：2
3、38U 206Pb84He由实验测得238U的半衰期为4.51109 y，试求该陨石的年龄。（答案：2.36109年）解：每克陨石中含He：mol最开始每克陨石中含238U的量：mol现在每克陨石中含238U的量：mol衰变速率常数：6303.01 K时甲酸甲酯在85%的碱性水溶液中水解，其速率常数为4.53 mol-1Ls-1。(1) 若酯和碱的初始浓度均为110-3molL-1，试求半衰期。(2 )若两种浓度，一种减半，另一种加倍，试求量少者消耗一半所需的时间为多少。（答案：220.8，82.36s）解：(1) 甲酸甲酯的水解反应为二级反应，且当酯和碱的初始浓度相等时，其速率方程可化为纯二
4、级反应速率方程形式：故：(2) 且当酯和碱的初始浓度不相等时为混二级反应，将反应简写为： A + B 产物设t = 0时： 210-3 0.510-3 0即：cA,0 = 210-3 molL-1，cB,0 = 0.510-3 molL-1，则动力学方程为：对B：当cB = 0.5cB,0时，必有：cA =1.7510-3 molL-1，所以对B而言：7在1100 K，测得NH3在W上起催化反应的数据如下：NH3的初压p0/Pa35330173327733半衰期t1/2/min7.63.71.7(1) 试证明该反应近似为零级反应；(2)求速率常数0。 （答案：38.66Pas-1）解：(1)
5、对于纯零级反应，其半衰期为，则用尝试法计算k0如下：Pas-1 ;Pas-1Pas-1k0值基本为常数，因此为零级反应。(2) 该反应的速率常数k0值可取以上3个计算值的平均值：k0 =38.56 Pas-181033 K时2O的热分解获得如右数据：Pa 38663 479961/2s 265 216 求：(1) 反应级数；(2) 起始压强101325 Pa时的半衰期。（答案：二级，101.6s）解：(1) 因t1/2与p0有关，故不可能是一级反应。用零级试尝：，得：k0,1 = 72.95及k0,2 = 111.10用二级试尝：，得：k2,1 = 9.7610-8及k2,2 =9.6510-
6、8显然应为二级反应，平均：k2 = 9.7110-8 (Pas)-1(2) 当p0=101325 Pa时，9300 K时N2O5分解过程中测得不同时刻N2O5的压强如下：0142284426pN2O5Pa7999339997199989999（）求反应级数和速率常数； (2) 100 时N2O5的转化率及瞬时速率。（答案：（1）一级，4.8810-3s-1 （2）38.6%，237.7Pas-1 ）解： N2O5 N2O4 + 0.5O2(1) 按一级反应动力学公式试算得：t /s 0 142 248 426 0 0.693 1.38 2.078k /s-1 0.00488 0.00486 0
7、.00486故为一级反应，平均：k = 0.00487 s-1(2) t =100s时0.00487100= ，pN2O5 = 49166Pa转化率 = (79993-49166) / 79993 = 38.54%r N2O5= 0.0048749166 = 239.4Pas-110777 K时二甲醚分解实验测得如下数据，试用微分法确定反应CH3OCH3 CH4COH2的级数。0390665119522403155体系Pa4159754396623957492795192103858124123提示：先由p体系及p求出不同时的pCH3OCH3，作图求-dpdt（答案：一级）解： CH3OCH3
8、 CH4COH2t =0 p0t = t pCH3OCH3pCH4 = pCO = pH2 = p0- pCH3OCH3p体系= pi = 3p0- 2 pCH3OCH3pCH3OCH3 =3p0-p体系/2从而得到下列数据：t /s0390665119522403155pCH3OCH3 /Pa415973519731198249321479910466d/dt16.4114.5411.029.694.74k1044.664.664.744.554.52注：d/dt= ( p0 - pCH3OCH3) / t，k = ( d/dt)(1/ pCH3OCH3)所得速率常数基本不变，故为一级反应。
9、11设有对峙反应A ，A的初始浓度为1.89 molL-1，时间测得D的浓度x为：1803004209001 440x(molL-1)0.20.330.430.781.051.58(xe)求正、逆反应速率常数。（答案：6.2910-4 s-1，1.2310-4s-1）解：对峙反应 A 为正、逆反应均为一级反应，则：，试算得如下数据：t1803004209001440k11046.2866.5286.3236.3226.341k-11041.2331.2401.24412某金属的氧化反应服从下列抛物线方程式：y2k1tk2，式中y为在反应到t时间的金属氧化膜的厚度，试确定该金属氧化是几级。（答案
10、：-1级）解：y2k1tk2，2ydy = k1dt则，故此反应为 -1级反应。13反应2NOO2 = 2NO2的历程可能是：NONO N2O2， N2O2 2NO , N2O2 + O2 2NO2试导出解：，按稳态法处理，即，可求得：14五氧化二氮的分解为典型的一级反应，分解产物为NO2和O2，下面的复杂反应历程推断较之单分子反应历程推断来得正确。试按复杂反应历程推导分解速率方程式。 N2O5 NO2+ NO3 , NO2+ NO3 N2O5 , NO2+ NO3 NO2 + O2 + NO （慢）, NO + NO3 2NO2（答案：）解：总反应为：2N2O5 ? 4NO2+O2，而：解得
11、：，15某反应的历程为A ?D ， D + C G，试证明该反应在高压下是一级反应，在低压下是二级反应。解：因为：，而：得：，高压时，k3cCk2，为一级反应低压时，k3cCk-1，故可以把A的分解当作单向一级反应处理，则所需时间就是A物的半衰期：24醋酸酐的分解反应是一级反应。该反应的活化能Ea144.35 kJmol-1。已知557.15 K时这个反应的k3.310-2s-1。现要控制该反应在10 min内转化率达90%，试确定反应温度应控制在多少度。（答案：521.2 K）解：对一级反应有：所以要使反应在10 min内转化率达90%，温度应为T2，则：解得：T2 = 521.2 K25反
12、应 2NOO2= 2NO2的一个可能历程为：NONO N2O2（快）；k3N2O2 + O2 2NO2（慢）。已知Ea,182 kJmol-1，E a,220.5 kJmol-1，E a,382 kJmol-1，求总反应的表观活化能为多少。（答案：143.5 kJmol-1）解：采用平衡近似法，根据反应历程可得：则，因为k3为慢反应步骤的速率常数，即可取k30故Ea = E1+E3-E2= 82+82-20.5=143.5 kJmol-126.。根据过渡状态反应速率理论求证n分子气相反应： 产物的活化能EarHnRT。提示：kn(kBT/h)K，EarURT，rUrH(n)RT，n1-nK证：
13、设： ?而，又，Ea= rU + RTrU = rH (n)RT= rH -(1-n)RTEa= rH - (1-n)RT + RT = rH nRT27在无催化剂存在时，反应 2HI= H2T2的活化能为183920 Jmol-1，当用铂作催化剂时改变了其反应历程，活化能降低为104500 Jmol-1。若反应在575 K时进行，求铂催化剂使此反应速率增加的倍数。（答案：1.6107）解：根据阿仑尼乌斯方程得：，28某气相反应 2为双分子反应，其活化能为1105Jmol-1，已知A的相对分子质量为60，分子的直径为0.35 nm，试计算300 K时该反应的速率常数。（答案：4.110-7 m
14、oldm-3s-1）解：29已知在高压下N2O5的分解为一级反应，298.15K时3.3510-5s-1，338.15K时4.8010-3s-1。试求分解反应的和。（答案：101506.33Jmol-1，143.84Jmol-1K-1）解：，两边取对数：， 联立上两方程得：以下是大学体验英语综合教程2(第三版)课后翻译答案Unit11. 任何年满18岁的人都有资格投票。(be eligible to, vote)Answer:Anyone over the age of 18 is eligible to vote.2. 每学期开学前，这些奖学金的申请表格就会由学校发给每一个学生。(apply
15、 for, scholarship)Answer:A form to apply for these scholarships is sent by the university to every student before the start of every semester.3. 遵照医生的建议，我决定戒烟。(on the advice of)Answer:On the advice of my doctor, I decided to give up smoking.4. 公园位于县城的正中央。(be located in)Answer:The park is located rig
16、ht in the center of town.5. 这所大学提供了我们所需的所有材料和设备。(facilities)Answer:The university provides all the materials and facilities we desire.1. 他们花了多年的时间寻找内心的平静，但是收效甚微。(search for)Answer:They spent many years searching for peace of mind, but with little success.2. 这种新药的成功研制已经使许多疾病的治疗发生了根本性的变革。(revolutioniz
17、e)Answer:The successful development of the new drug has revolutionized the treatment of many diseases.3. 由于这个国家的经济不景气，这家公司濒于破产。(on the edge of)Answer:The company is on the edge of bankruptcy due to the economic depression in the country.4. 大学毕业后他成为了一名护士。他认为护士这一职业可能很有发展前途。(rewarding)Answer:He became
18、a nurse after college. He thought nursing could be a very rewarding career.5. 他像往常一样在文件上签了名。(just as)Answer:He signed his name on the paper just as he has always done it.Unit21. 警察们正忙着填写关于这场事故的各种表格。(fill out)Answer:The policemen are busy fi lling out forms about the accident.2. 我想在还车之前把油箱加满。(fill up
19、, fuel tank)Answer:I want to fi ll up the fuel tank before returning the car.3. 如果你要投诉，最好遵循正确的程序。(follow the procedure)Answer:If you want to make a complaint, youd better follow the correct procedure.4. 要不是约翰帮忙，我们绝不会这么快就完成实验。(without)Answer:We couldnt have fi nished the experiment so soon without Jo
20、hns help.5. 暴风雨之后，岸边的人们焦急地搜索湖面以期发现小船的踪迹。(scan for)Answer:After the storm, the people on the shore anxiously scanned the lake for any sign of the boat.1. 这个国家不大，但是在国际事务中它却发挥着重要作用。(play a role)Answer:This country is not big, but it plays an important role in international affairs.2. 正是在我叔叔的帮助下，我得以克服困难
21、，按时完成了任务。(it is . that)Answer:It was with the help of my uncle that I overcame the difficulty and completed the assignment in time.3. 毕业时他决定留在北京，而他最好的朋友却选择了去西藏。(while)Answer:While he decided to stay in Beijing upon graduation, his best friend chose to go to Tibet.4. 在这次校园英语演讲比赛中，我们班的玛丽获得了第三名。(come i
22、n)Answer:In this Campus English Speaking Contest, Mary from our class came in third.5. 你应该知道学习弹钢琴需要有时间，有金钱，还要有毅力。(as well as)Answer:You should know that it takes time, money as well as perseverance to learn to play the piano.Unit31. 我发现量入为出地过日子越来越难了。(increasingly)Answer:I find it increasingly diffic
23、ult to live within my income.2. 现代政治家们都试图以电视讲话来影响普通百姓。(reach out)Answer:Modern politicians try to reach out to ordinary people in their TV speeches.3. 应该帮助学生对人生采取积极的态度。(adopt)Answer:Pupils should be helped to adopt a positive attitude to life.4. 希望全班同学参加这些讨论。(participate in)Answer:Everyone in the cl
24、ass is expected to participate in these discussions.5. 如果你犯了罪就必须受到惩罚。(crime)Answer:If you commit a crime you must expect to be punished.1.儿子的死让老妇人变得麻木痴呆了。(numb)Answer:The old woman was numbed by her sons death.2.身处所有这些烦恼之中，他依然能保持乐观。(in the midst)Answer:In the midst of all troubles, he managed to rem
25、ain cheerful.3. 虽有困难，他们还是设法坚持试验下去。(carry on)Answer:They managed to carry on their experiments in spite of the difficulties.4.我们必须淘汰不合格的申请人。(weed out)Answer:We have to weed out unqualified applicants.5. 医生要他减少抽烟。(cut down on)Answer:The doctor told him to cut down on smoking.Unit41.她在公共汽车站一直等到末班车进站。(c
26、ome in)Answer:She waited at the bus stop until the last bus came in.2.如果我们能帮得上忙，尽管和我们联系。(contact)Answer:If there is any way we can be of assistance, please do not hesitate to contact us.3 .他需要多少船务人员才能使他的游艇航行？(crew, yacht)Answer:How many crew does he need to sail his yacht?4 .虽然她的新书没有上一本好，但是我还是喜欢它。(n
27、ot quite as)Answer:I enjoyed her new book though its not quite as good as her last one.5 .我从未遇到过如此善良的人。(never before)Answer:Never before have I met such a kind person.1.公共汽车放慢速度并停下，让那位乘客上车。(slow down)Answer:The bus slowed down and stopped to allow the passenger to get on board.2.许多车子都驶过去了，可是没有一辆愿意让我
28、们搭便车。(roll by)Answer:Many vehicles rolled by, but no one offered us a ride.3 .请勿践踏草地。(get off)Answer:Please get off the grass.4.他按妻子的吩咐，一下班就去了市场。(make ones way)Answer:He made his way to the marketplace right after work, as his wife had asked him to do.5 .值得庆幸的是，史蒂夫 (Steve) 从自行车上摔下来时没有摔断骨头。(luckily)A
29、nswer:Luckily, Steve didnt break any bones when he fell off his bike.Unit51. 我们得把感情放在一边，从专业的角度来对待这件事。(from a professional standpoint)Answer:We have to put aside our emotions and take it from a professional standpoint.2. 这部戏非常精彩，我很快就沉浸于激动人心的剧情之中。(lose oneself in)Answer:The play was so wonderful that
30、I soon lost myself in the excitement of it.3 .她没有什么爱好除非你把看电视也算是一种爱好。(unless)Answer:She hasnt got any hobbies unless you call watching TV a hobby.4. 他说他是直接从市长本人那里得到这个信息的。(first-hand)Answer:He said that he had got the information first-hand from the Mayor himself.5 .既然你不能回答这个问题，我们最好问问别人。(since)Answer:
31、Since you cant answer the question, perhaps wed better ask someone else.1. 由于公共汽车司机突然刹车，旅客们都不由自主地向前摔倒。(brake, pitch forward)Answer:All the passengers pitched forward because the bus driver braked sharply.2. 这个协议将冲破对自由贸易设置的障碍。(break through, obstacle)Answer:This agreement will break through the obsta
32、cles to free trade.3 .我刚放下叫出租车的电话，车就来了。(soon after)Answer:The taxi arrived soon after I rang for it.4. 在过去，不管我什么时候到家，我父母总会等我。(no matter)Answer:My parents always waited up for me no matter what time I got home.5 .由于没有一方愿意让步，两个公司之间的对话完全破裂了。(break down)Answer:Talks between the two companies completely
33、broke down, because neither of them wanted to give in.Unit61. 那件工作很难做，不过我想试试看。(have a shot)Answer:Its a difficult job, but Id like to have a shot.2. 这是一本关于商务实践而非理论的书。(as opposed to)Answer:This is a book about business practice as opposed to theory.3. 社会活动从未耽误她的学习。(in the way)Answer:Social activities
34、 never get in the way of her studies.4. 直到1911年人们才发现第一种维生素。(It is not until . that)Answer:It was not until 1911 that the first of the vitamins was identified.5. 尽管年事已高，爷爷每天还帮忙做家务。(despite)Answer:Despite advanced years, Grandpa helps do housework every day.1. 我们的婚姻很幸福，但我们也曾经历过许多坎坷。(ups and downs)Answ
35、er:Our marriage is happy but weve had many ups and downs.2. 许多外语教师常常在课堂上自顾自地讲得太多。(be inclined to)Answer:Many teachers of foreign languages are inclined to talk too much themselves in class.3. 那位著名演员每天早晨锻炼一小时以保持健康。(work out)Answer:The famous actor keeps fit by working out for an hour every morning.4.
36、 与他促膝长谈之后，她的怀疑消失了。(melt away)Answer:After a long heart-to-heart talk with him, her suspicion melted away.5. 目前我们没有职位空缺，但我们肯定会记住您的申请。(keep in mind)Answer:We have no vacancies now, but well certainly keep your application in mind.Unit71. 他并不后悔说过的话，只是觉得他完全可以不用这种方式表达。(could have done)Answer:He did not r
37、egret what he had said but felt that he could have expressed it differently.2. 我们最好等到12月14日。那时大卫已考完试，就能和我们一起去度假了。(will have done)Answer:Wed better wait till 14 December. David will have had his exam by then, so hell be able to go on holiday with us.3. 他正在做一个新项目，年底前必须完成。(work on)Answer:Hes working on
38、 a new project which has to be finished by the end of the year.4. 他们让我们使用他们的实验室，作为回报，我们则让他们分享研究成果。(in return)Answer:They are letting us use their lab, and in return, we are sharing with them the results of our research.5. 诸如打电话、听电话一类的事情占用了这位秘书的大部分时间。(take up)Answer:Such things as making and answerin
39、g telephone calls take up most of the secretarys time.1. 他们把房子卖了后就到加拿大和女儿住在一起。(go off) Answer:They sold their house and went off to live in Canada with their daughter.2. 你下星期这个时候会在干什么？还是像平常一样干活。(will be doing)Answer:What will you be doing this time next week?Ill be working as usual.3. 他既聪明又勤奋，不久就接管了
40、杂志的编辑工作。(editing; before long)Answer:He was intelligent and hard-working and before long he took over the editing of the magazine.4. 你话还没说完别人就挂断电话，难道你不恼火吗？(hang up)Answer:Dont you hate it when someone hangs up on you before you finish speaking?5. 让他们感到惊恐的是，他们的房顶着火了。(to ones horror)Answer:To their horror, the roof of their house caught fire.
