中南大学物化课后习题答案 7 章 化学动力学.doc

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：238u 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) 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 =9.6510-8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 0.00486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 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。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：-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：，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：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 moldm-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 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 right 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。(revolutionize)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 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, 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 johns 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，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 in)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 difficult 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 class 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 remain 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。(come 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。(not 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)answer: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 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: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 obstacles 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 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 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)answer: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. 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 regret what he had said but felt that h