中南大學(xué)物化課后習(xí)題答案 7 章 化學(xué)動(dòng)力學(xué)

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1、第7章 化學(xué)動(dòng)力學(xué)1以氨的分解反應(yīng)2NH3= N23H2為例，導(dǎo)出反應(yīng)進(jìn)度的增加速率與， 之間的關(guān)系，并說明何者用于反應(yīng)速率時(shí)與選擇哪種物質(zhì)為準(zhǔn)無關(guān)。解：，2甲醇的合成反應(yīng)如下：CO22 = CH3OH已知，求，各為多少?（答案：2.44，4.88moldm-3h-1）解：，3下列復(fù)雜反應(yīng)由所示若干簡(jiǎn)單反應(yīng)組成，試根據(jù)質(zhì)量作用定律寫出以各物質(zhì)為準(zhǔn)的速率方程式。(1) (2) (3) (4) 解：(1) ，(2) (3) (4) 4理想氣體反應(yīng) 2N2O5 4NO2O2，在298.15 K的速率常數(shù)k是1.7310-5-1，速率方程為。(1)計(jì)算在298.15K、12.0 dm3的容器中，此反應(yīng)

2、的和即各為多少?(2)計(jì)算在(1)的反應(yīng)條件下，1s內(nèi)被分解的N2O5分子數(shù)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個(gè)分子5已知每克隕石中含238U 6.310-8，He為20.7710st1:chmetcnv UnitName=cm SourceValue=6 HasSpace=False Negative=True NumberType=1 TCSC=0-6cm3(標(biāo)準(zhǔn)狀態(tài)下)，238U的衰變?yōu)橐患?jí)反應(yīng)：2

3、38U 206Pb84He由實(shí)驗(yàn)測(cè)得238U的半衰期為4.51109 y，試求該隕石的年齡。（答案：2.36109年）解：每克隕石中含He：mol最開始每克隕石中含238U的量：mol現(xiàn)在每克隕石中含238U的量：mol衰變速率常數(shù)：6303.01 K時(shí)甲酸甲酯在85%的堿性水溶液中水解，其速率常數(shù)為4.53 mol-1Ls-1。(1) 若酯和堿的初始濃度均為110-3molL-1，試求半衰期。(2 )若兩種濃度，一種減半，另一種加倍，試求量少者消耗一半所需的時(shí)間為多少。（答案：220.8，82.36s）解：(1) 甲酸甲酯的水解反應(yīng)為二級(jí)反應(yīng)，且當(dāng)酯和堿的初始濃度相等時(shí)，其速率方程可化為純二

4、級(jí)反應(yīng)速率方程形式：故：(2) 且當(dāng)酯和堿的初始濃度不相等時(shí)為混二級(jí)反應(yīng)，將反應(yīng)簡(jiǎn)寫為： A + B 產(chǎn)物設(shè)t = 0時(shí)： 210-3 0.510-3 0即：cA,0 = 210-3 molL-1，cB,0 = 0.510-3 molL-1，則動(dòng)力學(xué)方程為：對(duì)B：當(dāng)cB = 0.5cB,0時(shí)，必有：cA =1.7510-3 molL-1，所以對(duì)B而言：7在1100 K，測(cè)得NH3在W上起催化反應(yīng)的數(shù)據(jù)如下：NH3的初壓p0/Pa35330173327733半衰期t1/2/min7.63.71.7(1) 試證明該反應(yīng)近似為零級(jí)反應(yīng)；(2)求速率常數(shù)0。 （答案：38.66Pas-1）解：(1)

5、對(duì)于純零級(jí)反應(yīng)，其半衰期為，則用嘗試法計(jì)算k0如下：Pas-1 ;Pas-1Pas-1k0值基本為常數(shù)，因此為零級(jí)反應(yīng)。(2) 該反應(yīng)的速率常數(shù)k0值可取以上3個(gè)計(jì)算值的平均值：k0 =38.56 Pas-181033 K時(shí)2O的熱分解獲得如右數(shù)據(jù)：Pa 38663 479961/2s 265 216 求：(1) 反應(yīng)級(jí)數(shù)；(2) 起始?jí)簭?qiáng)101325 Pa時(shí)的半衰期。（答案：二級(jí)，101.6s）解：(1) 因t1/2與p0有關(guān)，故不可能是一級(jí)反應(yīng)。用零級(jí)試嘗：，得：k0,1 = 72.95及k0,2 = 111.10用二級(jí)試嘗：，得：k2,1 = 9.7610-8及k2,2 =9.6510-

6、8顯然應(yīng)為二級(jí)反應(yīng)，平均：k2 = 9.7110-8 (Pas)-1(2) 當(dāng)p0=101325 Pa時(shí)，9300 K時(shí)N2O5分解過程中測(cè)得不同時(shí)刻N(yùn)2O5的壓強(qiáng)如下：0142284426pN2O5Pa7999339997199989999（）求反應(yīng)級(jí)數(shù)和速率常數(shù)； (2) 100 時(shí)N2O5的轉(zhuǎn)化率及瞬時(shí)速率。（答案：（1）一級(jí)，4.8810-3s-1 （2）38.6%，237.7Pas-1 ）解： N2O5 N2O4 + 0.5O2(1) 按一級(jí)反應(yīng)動(dòng)力學(xué)公式試算得：t /s 0 142 248 426 0 0.693 1.38 2.078k /s-1 0.00488 0.00486 0

7、.00486故為一級(jí)反應(yīng)，平均：k = 0.00487 s-1(2) t =100s時(shí)0.00487100= ，pN2O5 = 49166Pa轉(zhuǎn)化率 = (79993-49166) / 79993 = 38.54%r N2O5= 0.0048749166 = 239.4Pas-110777 K時(shí)二甲醚分解實(shí)驗(yàn)測(cè)得如下數(shù)據(jù)，試用微分法確定反應(yīng)CH3OCH3 CH4COH2的級(jí)數(shù)。0390665119522403155體系Pa4159754396623957492795192103858124123提示：先由p體系及p求出不同時(shí)的pCH3OCH3，作圖求-dpdt（答案：一級(jí)）解： CH3OCH3

8、 CH4COH2t =0 p0t = t pCH3OCH3pCH4 = pCO = pH2 = p0- pCH3OCH3p體系= pi = 3p0- 2 pCH3OCH3pCH3OCH3 =3p0-p體系/2從而得到下列數(shù)據(jù)：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)所得速率常數(shù)基本不變，故為一級(jí)反應(yīng)。

9、11設(shè)有對(duì)峙反應(yīng)A ，A的初始濃度為1.89 molL-1，時(shí)間測(cè)得D的濃度x為：1803004209001 440x(molL-1)0.20.330.430.781.051.58(xe)求正、逆反應(yīng)速率常數(shù)。（答案：6.2910-4 s-1，1.2310-4s-1）解：對(duì)峙反應(yīng) A 為正、逆反應(yīng)均為一級(jí)反應(yīng)，則：，試算得如下數(shù)據(jù)：t1803004209001440k11046.2866.5286.3236.3226.341k-11041.2331.2401.24412某金屬的氧化反應(yīng)服從下列拋物線方程式：y2k1tk2，式中y為在反應(yīng)到t時(shí)間的金屬氧化膜的厚度，試確定該金屬氧化是幾級(jí)。（答案

10、：-1級(jí)）解：y2k1tk2，2ydy = k1dt則，故此反應(yīng)為 -1級(jí)反應(yīng)。13反應(yīng)2NOO2 = 2NO2的歷程可能是：NONO N2O2， N2O2 2NO , N2O2 + O2 2NO2試導(dǎo)出解：，按穩(wěn)態(tài)法處理，即，可求得：14五氧化二氮的分解為典型的一級(jí)反應(yīng)，分解產(chǎn)物為NO2和O2，下面的復(fù)雜反應(yīng)歷程推斷較之單分子反應(yīng)歷程推斷來得正確。試按復(fù)雜反應(yīng)歷程推導(dǎo)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：總反應(yīng)為：2N2O5 ? 4NO2+O2，而：解得

11、：，15某反應(yīng)的歷程為A ?D ， D + C G，試證明該反應(yīng)在高壓下是一級(jí)反應(yīng)，在低壓下是二級(jí)反應(yīng)。解：因?yàn)椋?，而：得：，高壓時(shí)，k3cCk2，為一級(jí)反應(yīng)低壓時(shí)，k3cCk-1，故可以把A的分解當(dāng)作單向一級(jí)反應(yīng)處理，則所需時(shí)間就是A物的半衰期：24醋酸酐的分解反應(yīng)是一級(jí)反應(yīng)。該反應(yīng)的活化能Ea144.35 kJmol-1。已知557.15 K時(shí)這個(gè)反應(yīng)的k3.310-2s-1?，F(xiàn)要控制該反應(yīng)在10 min內(nèi)轉(zhuǎn)化率達(dá)90%，試確定反應(yīng)溫度應(yīng)控制在多少度。（答案：521.2 K）解：對(duì)一級(jí)反應(yīng)有：所以要使反應(yīng)在10 min內(nèi)轉(zhuǎn)化率達(dá)90%，溫度應(yīng)為T2，則：解得：T2 = 521.2 K25反

12、應(yīng) 2NOO2= 2NO2的一個(gè)可能歷程為：NONO N2O2（快）；k3N2O2 + O2 2NO2（慢）。已知Ea,182 kJmol-1，E a,220.5 kJmol-1，E a,382 kJmol-1，求總反應(yīng)的表觀活化能為多少。（答案：143.5 kJmol-1）解：采用平衡近似法，根據(jù)反應(yīng)歷程可得：則，因?yàn)閗3為慢反應(yīng)步驟的速率常數(shù)，即可取k30故Ea = E1+E3-E2= 82+82-20.5=143.5 kJmol-126.。根據(jù)過渡狀態(tài)反應(yīng)速率理論求證n分子氣相反應(yīng)： 產(chǎn)物的活化能EarHnRT。提示：kn(kBT/h)K，EarURT，rUrH(n)RT，n1-nK證：

13、設(shè)： ?而，又，Ea= rU + RTrU = rH (n)RT= rH -(1-n)RTEa= rH - (1-n)RT + RT = rH nRT27在無催化劑存在時(shí)，反應(yīng) 2HI= H2T2的活化能為183920 Jmol-1，當(dāng)用鉑作催化劑時(shí)改變了其反應(yīng)歷程，活化能降低為104500 Jmol-1。若反應(yīng)在575 K時(shí)進(jìn)行，求鉑催化劑使此反應(yīng)速率增加的倍數(shù)。（答案：1.6107）解：根據(jù)阿侖尼烏斯方程得：，28某氣相反應(yīng) 2為雙分子反應(yīng)，其活化能為1105Jmol-1，已知A的相對(duì)分子質(zhì)量為60，分子的直徑為0.35 nm，試計(jì)算300 K時(shí)該反應(yīng)的速率常數(shù)。（答案：4.110-7 m

14、oldm-3s-1）解：29已知在高壓下N2O5的分解為一級(jí)反應(yīng)，298.15K時(shí)3.3510-5s-1，338.15K時(shí)4.8010-3s-1。試求分解反應(yīng)的和。（答案：101506.33Jmol-1，143.84Jmol-1K-1）解：，兩邊取對(duì)數(shù)：， 聯(lián)立上兩方程得：以下是大學(xué)體驗(yàn)英語綜合教程2(第三版)課后翻譯答案Unit11. 任何年滿18歲的人都有資格投票。(be eligible to, vote)Answer:Anyone over the age of 18 is eligible to vote.2. 每學(xué)期開學(xué)前，這些獎(jiǎng)學(xué)金的申請(qǐng)表格就會(huì)由學(xué)校發(fā)給每一個(gè)學(xué)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. 遵照醫(yī)生的建議，我決定戒煙。(on the advice of)Answer:On the advice of my doctor, I decided to give up smoking.4. 公園位于縣城的正中央。(be located in)Answer:The park is located rig

16、ht in the center of town.5. 這所大學(xué)提供了我們所需的所有材料和設(shè)備。(facilities)Answer:The university provides all the materials and facilities we desire.1. 他們花了多年的時(shí)間尋找內(nèi)心的平靜，但是收效甚微。(search for)Answer:They spent many years searching for peace of mind, but with little success.2. 這種新藥的成功研制已經(jīng)使許多疾病的治療發(fā)生了根本性的變革。(revolutioniz

17、e)Answer:The successful development of the new drug has revolutionized the treatment of many diseases.3. 由于這個(gè)國(guó)家的經(jīng)濟(jì)不景氣，這家公司瀕于破產(chǎn)。(on the edge of)Answer:The company is on the edge of bankruptcy due to the economic depression in the country.4. 大學(xué)畢業(yè)后他成為了一名護(hù)士。他認(rèn)為護(hù)士這一職業(yè)可能很有發(fā)展前途。(rewarding)Answer:He became

18、a nurse after college. He thought nursing could be a very rewarding career.5. 他像往常一樣在文件上簽了名。(just as)Answer:He signed his name on the paper just as he has always done it.Unit21. 警察們正忙著填寫關(guān)于這場(chǎng)事故的各種表格。(fill out)Answer:The policemen are busy fi lling out forms about the accident.2. 我想在還車之前把油箱加滿。(fill up

19、, fuel tank)Answer:I want to fi ll up the fuel tank before returning the car.3. 如果你要投訴，最好遵循正確的程序。(follow the procedure)Answer:If you want to make a complaint, youd better follow the correct procedure.4. 要不是約翰幫忙，我們絕不會(huì)這么快就完成實(shí)驗(yàn)。(without)Answer:We couldnt have fi nished the experiment so soon without Jo

20、hns help.5. 暴風(fēng)雨之后，岸邊的人們焦急地搜索湖面以期發(fā)現(xiàn)小船的蹤跡。(scan for)Answer:After the storm, the people on the shore anxiously scanned the lake for any sign of the boat.1. 這個(gè)國(guó)家不大，但是在國(guó)際事務(wù)中它卻發(fā)揮著重要作用。(play a role)Answer:This country is not big, but it plays an important role in international affairs.2. 正是在我叔叔的幫助下，我得以克服困難

21、，按時(shí)完成了任務(wù)。(it is . that)Answer:It was with the help of my uncle that I overcame the difficulty and completed the assignment in time.3. 畢業(yè)時(shí)他決定留在北京，而他最好的朋友卻選擇了去西藏。(while)Answer:While he decided to stay in Beijing upon graduation, his best friend chose to go to Tibet.4. 在這次校園英語演講比賽中，我們班的瑪麗獲得了第三名。(come i

22、n)Answer:In this Campus English Speaking Contest, Mary from our class came in third.5. 你應(yīng)該知道學(xué)習(xí)彈鋼琴需要有時(shí)間，有金錢，還要有毅力。(as well as)Answer:You should know that it takes time, money as well as perseverance to learn to play the piano.Unit31. 我發(fā)現(xiàn)量入為出地過日子越來越難了。(increasingly)Answer:I find it increasingly diffic

23、ult to live within my income.2. 現(xiàn)代政治家們都試圖以電視講話來影響普通百姓。(reach out)Answer:Modern politicians try to reach out to ordinary people in their TV speeches.3. 應(yīng)該幫助學(xué)生對(duì)人生采取積極的態(tài)度。(adopt)Answer:Pupils should be helped to adopt a positive attitude to life.4. 希望全班同學(xué)參加這些討論。(participate in)Answer:Everyone in the cl

24、ass is expected to participate in these discussions.5. 如果你犯了罪就必須受到懲罰。(crime)Answer:If you commit a crime you must expect to be punished.1.兒子的死讓老婦人變得麻木癡呆了。(numb)Answer:The old woman was numbed by her sons death.2.身處所有這些煩惱之中，他依然能保持樂觀。(in the midst)Answer:In the midst of all troubles, he managed to rem

25、ain cheerful.3. 雖有困難，他們還是設(shè)法堅(jiān)持試驗(yàn)下去。(carry on)Answer:They managed to carry on their experiments in spite of the difficulties.4.我們必須淘汰不合格的申請(qǐng)人。(weed out)Answer:We have to weed out unqualified applicants.5. 醫(yī)生要他減少抽煙。(cut down on)Answer:The doctor told him to cut down on smoking.Unit41.她在公共汽車站一直等到末班車進(jìn)站。(c

26、ome in)Answer:She waited at the bus stop until the last bus came in.2.如果我們能幫得上忙，盡管和我們聯(lián)系。(contact)Answer:If there is any way we can be of assistance, please do not hesitate to contact us.3 .他需要多少船務(wù)人員才能使他的游艇航行？(crew, yacht)Answer:How many crew does he need to sail his yacht?4 .雖然她的新書沒有上一本好，但是我還是喜歡它。(n

27、ot quite as)Answer:I enjoyed her new book though its not quite as good as her last one.5 .我從未遇到過如此善良的人。(never before)Answer:Never before have I met such a kind person.1.公共汽車放慢速度并停下，讓那位乘客上車。(slow down)Answer:The bus slowed down and stopped to allow the passenger to get on board.2.許多車子都駛過去了，可是沒有一輛愿意讓我

28、們搭便車。(roll by)Answer:Many vehicles rolled by, but no one offered us a ride.3 .請(qǐng)勿踐踏草地。(get off)Answer:Please get off the grass.4.他按妻子的吩咐，一下班就去了市場(chǎng)。(make ones way)Answer:He made his way to the marketplace right after work, as his wife had asked him to do.5 .值得慶幸的是，史蒂夫 (Steve) 從自行車上摔下來時(shí)沒有摔斷骨頭。(luckily)A

29、nswer:Luckily, Steve didnt break any bones when he fell off his bike.Unit51. 我們得把感情放在一邊，從專業(yè)的角度來對(duì)待這件事。(from a professional standpoint)Answer:We have to put aside our emotions and take it from a professional standpoint.2. 這部戲非常精彩，我很快就沉浸于激動(dòng)人心的劇情之中。(lose oneself in)Answer:The play was so wonderful that

30、I soon lost myself in the excitement of it.3 .她沒有什么愛好除非你把看電視也算是一種愛好。(unless)Answer:She hasnt got any hobbies unless you call watching TV a hobby.4. 他說他是直接從市長(zhǎng)本人那里得到這個(gè)信息的。(first-hand)Answer:He said that he had got the information first-hand from the Mayor himself.5 .既然你不能回答這個(gè)問題，我們最好問問別人。(since)Answer:

31、Since you cant answer the question, perhaps wed better ask someone else.1. 由于公共汽車司機(jī)突然剎車，旅客們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. 這個(gè)協(xié)議將沖破對(duì)自由貿(mào)易設(shè)置的障礙。(break through, obstacle)Answer:This agreement will break through the obsta

32、cles to free trade.3 .我剛放下叫出租車的電話，車就來了。(soon after)Answer:The taxi arrived soon after I rang for it.4. 在過去，不管我什么時(shí)候到家，我父母總會(huì)等我。(no matter)Answer:My parents always waited up for me no matter what time I got home.5 .由于沒有一方愿意讓步，兩個(gè)公司之間的對(duì)話完全破裂了。(break down)Answer:Talks between the two companies completely

33、broke down, because neither of them wanted to give in.Unit61. 那件工作很難做，不過我想試試看。(have a shot)Answer:Its a difficult job, but Id like to have a shot.2. 這是一本關(guān)于商務(wù)實(shí)踐而非理論的書。(as opposed to)Answer:This is a book about business practice as opposed to theory.3. 社會(huì)活動(dòng)從未耽誤她的學(xué)習(xí)。(in the way)Answer:Social activities

34、 never get in the way of her studies.4. 直到1911年人們才發(fā)現(xiàn)第一種維生素。(It is not until . that)Answer:It was not until 1911 that the first of the vitamins was identified.5. 盡管年事已高，爺爺每天還幫忙做家務(wù)。(despite)Answer:Despite advanced years, Grandpa helps do housework every day.1. 我們的婚姻很幸福，但我們也曾經(jīng)歷過許多坎坷。(ups and downs)Answ

35、er:Our marriage is happy but weve had many ups and downs.2. 許多外語教師常常在課堂上自顧自地講得太多。(be inclined to)Answer:Many teachers of foreign languages are inclined to talk too much themselves in class.3. 那位著名演員每天早晨鍛煉一小時(shí)以保持健康。(work out)Answer:The famous actor keeps fit by working out for an hour every morning.4.

36、 與他促膝長(zhǎng)談之后，她的懷疑消失了。(melt away)Answer:After a long heart-to-heart talk with him, her suspicion melted away.5. 目前我們沒有職位空缺，但我們肯定會(huì)記住您的申請(qǐng)。(keep in mind)Answer:We have no vacancies now, but well certainly keep your application in mind.Unit71. 他并不后悔說過的話，只是覺得他完全可以不用這種方式表達(dá)。(could have done)Answer:He did not r

37、egret what he had said but felt that he could have expressed it differently.2. 我們最好等到12月14日。那時(shí)大衛(wèi)已考完試，就能和我們一起去度假了。(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. 他正在做一個(gè)新項(xiàng)目，年底前必須完成。(work on)Answer:Hes working on

38、 a new project which has to be finished by the end of the year.4. 他們讓我們使用他們的實(shí)驗(yàn)室，作為回報(bào)，我們則讓他們分享研究成果。(in return)Answer:They are letting us use their lab, and in return, we are sharing with them the results of our research.5. 諸如打電話、聽電話一類的事情占用了這位秘書的大部分時(shí)間。(take up)Answer:Such things as making and answerin

39、g telephone calls take up most of the secretarys time.1. 他們把房子賣了后就到加拿大和女兒住在一起。(go off) Answer:They sold their house and went off to live in Canada with their daughter.2. 你下星期這個(gè)時(shí)候會(huì)在干什么？還是像平常一樣干活。(will be doing)Answer:What will you be doing this time next week?Ill be working as usual.3. 他既聰明又勤奮，不久就接管了

40、雜志的編輯工作。(editing; before long)Answer:He was intelligent and hard-working and before long he took over the editing of the magazine.4. 你話還沒說完別人就掛斷電話，難道你不惱火嗎？(hang up)Answer:Dont you hate it when someone hangs up on you before you finish speaking?5. 讓他們感到驚恐的是，他們的房頂著火了。(to ones horror)Answer:To their horror, the roof of their house caught fire.