sample of a reaction paper
Sample for review 外文杂志审稿样本

Molecules (ISSN 1420-3049) Referee Report Form/molecules/Manuscript ID: molecules-20071212-Soomro-beType of the paper: Full PaperTitle: Synthesis and Photochemistry of Polyene Cored Stilbenoid DendrimerAuthors: Shahid A. Soomro 1,* and Saeeda Aziz-Soomro 2E-mail: shahid.soomro@dafra.beReceived: 11 December 2007Manuscript file:/molecules/temp/molecules-20071212-Soomro-be.doc(size 104 KB)1. OVERALL EVALUATION2. OVERAL L RECOMMENDATION:3. Comments and Suggestions (for author to read)The manuscript “Synthesis and Photochemistry of Polyene Cored Stilbenoid Dendrimer” from Soomro et al. describes the synthesis of first generation dendrimer; a polyene core decorated with four stilbene chromophores. The photophysical study is presented.I cannot recommend the manuscript for publication in the present form; however, after major revision it could be considered again.1) IntroductionFirst the introduction is not clear. From the rest of the manuscript it becomes evident that authors direct their interest to light harvesting; however; in the introduction references are missing related to light harvesting dendrimers, e.g. by Müllen et al. and Moore et al. . Moreover, a reference regarding stilbenoid dendrimers, energy and electron transfer is also missing: H. Meier, M. Lehmann "STILBENOID DENDRIMERS - PREPARATION AND PROPERTIES " in H.S. Nalwa (Ed.), Encyclopedia of Nanoscience and Nanotechnology, Vol. 10, 95-106, American Scientific Publishers, Stevensons Ranch 2004.Page 2: a) The new structural concept was envisioned from H. Meiers Group (Angewandte Chemie 1998) almost parallel to the group of Prof. Luping Yu (JACS 1997).b) Since the authors, which performed obviously some work under supervision of Prof. H. Meier (see reference 3, 6 and the PhD thesis Mainz 2005; http://ubm.opus.hbz-nrw.de/frontdoor.php?source_opus=754); wrote “we envisioned”, I suppose that t hey meant their research group. However, nobody from the former authors (Angew. Chem. Int. Ed.1998, 37, 643-645) can be found among the authors. Thus, either the authors need to write “The structural concept was envisioned + references….” or they include simply one of the former authors. Furthermore, it remains unclear how the presented dendrimers are tunable with respect to page 2 of the introduction and what the authors mean by “two fold dendrimers”.A very similar publication where the conjugation between periphery and polyen core is broken by meta-substitution is cited as reference 12. However, the idea presented here, is already given in the later paper. The difference between reference 12 and the presented molecules should be already discussed in the introduction.2) Results and discussion – synthesisPage 3, the twofold Williamson’s ether synthesis leads to the product 5. It is quite normal that a slight excess of bromide 3 is used; however, the reaction is no bromination but an alkylation of a phenolic OH group!PCC should be explained in the text.I wonder if the chromatographic separation was really done on a SiO2 column. The solid phase is usually silica which has not the composition SiO2, which is quartz.The authors probably wanted to wr ite “with almost all-trans configuration”. Frequently, the Horner reaction gives less than 10 % Z configured stilbene. I would recommend to show an NMR spectrum where the integration shows the composition of the product. Moreover, authors should not use cis and trans, but E and Z.3) Results and discussion – UV/Vis and fluorescenceIt is well known, that interaction of transition dipoles leads to a so called Förster transfer of energy. It is certainly not a simple dipole-dipole interaction as described by the authors. This chapter should be completely revised.If the authors describe the excitation of different chromophores, they should give also the spectral band width of their light source.The fluorescence data is ill-interpreted. On the basis of Figure 1 and 2 the emission comes almost exclusively from the core. However, authors should show absorption and fluorescence data in one diagram also including the fluorescence below 400 nm.It is certainly not true that the only the peaks at 536, 552 are related with the core emission. The intensity of the emission spectra is in line with an exclusive core emission and light harvesting process; this part should be completely rewritten.Moreover, authors state that the core can not be separately excited! It is just the opposite!! The peripheral stilbene units can not selectively excited, however, the core can be excited selectively at the absorption edge at long wavelengths. I suppose that this is the reason that the emission is lowest when the chromophore is excited at 385 nm, compared to the irradiation at 314 nm.Finally, stilbenes and polyenes are each conjugated, i.e. they “have pi-conjugation” however, there is no conjugation between them!!4) ExperimentalSynthesis of 2 and 3 is known from literature and there is no need for their description unless there is a change of the procedure.There are many formal and spelling errors, e.g. numbers in formula need to be written as subscripts etc. and for the procedure of compound 5 it should be written phenyl ins tead of “phenly”; the amount of compounds should be given with uniform number of digits; etc.The elemental analysis for compounds 5 and 8 are wrong and are given without any comment!! Either they should be repeated or the reason for such a big deviation has to be explained. Certainly SiO2 should be silica.4. Comments (for editor)This manuscript describes the synthesis and characterization of a series of new diketopyrrolopyrrole-based luminophores and their photoluminescence properties as well in solution as in solid state. Absorption and emission characteristics were extensively analyzed and conclusions were drawn considering the molecular design in solution and in solid state. Also the single crystal structures of some of the DPP-compounds were elucidated and the structure-property relationships were consequently established. Therefore this manuscript meets the requirements for publishing in this journal. However, This paper requires very substantial / major revisions to both technical content and language. I suggest technical issues are dealt with first and then the language is polished after a second review.主题: 审稿各位同学: 你们好!请对文章是否新颖并有实质性的内容,实验设计是否合理,图表是否合理,英文是否通顺,结论是否合理等予以综合评价,并对发表前需作哪些修改和补充,提出具体意见,审稿意见请于10天内返回。
有机实验记录英文范例模板

有机实验记录英文范例模板Part1:反应前的装置描述1.1:A3L three-necked round bottom flask equipped with mechanical stirrer(or magnetic stirrer),addition funnel and thermometer(or Dean-Stock;drying tube)1.2:All flasks used in the reaction were heated under vacuum for30 minutes and purged with N2for10minutes.(无水反应装置)Part2:加料2.1:不同的顺序和表达2.1.1:A3L three-necked round bottom flask equipped with mechanical stirrer(or magnetic stirrer),addition funnel and thermometer(or Dean-Stock;drying tube)were charged with A(10mL,1mole),B(2g,mole)and C(50mL),2.1.1.1:a solution of D(10g,1mole)in E(20mL)was added dropwise (via addition funnel or syringe)at10oC(or while maintaining gentle reflux;while keeping inner temperature between10oC–30oC)under N2(液体滴加到反应液中)2.1.1.2:D(10g,1mole)was added in portions during a period of1hr (固体分批加入到反应液中)2.1.1.3:D(10g,1mole)and E(20mL)were added in turn.2.2:To a solution(mixture,suspension or slurry)of A(10mL,1mole) and B(2g,mole)in C(50mL)2.2.1:was added dropwise a solution of D(10g,1mole)in E(20mL)with stirring at10oC(or while maintaining gentle reflux;while keeping inner temperature between10oC–30oC)under N22.2.2:was added D(10g,1mole)in portions duringa period of1hr 2.2.3:were added D(10g,1mole)and E(20mL)in turn2.3:2.3.1:A solution of D(10g,1mole)in E(20mL)was added dropwise intoa solution(mixture or suspension)of A(10mL,1mole)and B(2g,mole) in C(50mL)at10oC(or while maintaining gentle reflux;while keeping inner temperature between10oC–30oC)under N2.2.3.2:D(10g,1mole)was added into a solution(mixture or suspension) of A(10mL,1mole)and B(2g,mole)in C(50mL)in portions2.3.3:D(10g,1mole)and E(20mL)were added into a solution(mixture or suspension)of A(10mL,1mole)and B(2g,mole)in C(50mL)in turn2.4:2.4.1:A solution of BuLi or BH3/THF(10mL,1mole,2.5M in hexane)was cannulated into addition funnel or into a solution A in solvent B2.4.2:A solution of BuLi or BH3/THF(10mL,1mole,2.5M in hexane)was added into a solution of A in solvent B via cannula,dropping funnel or syringe over a period of hrsPart3:反应3.1:无溶剂反应A(1g,1mol)and B(1g,1mol)were dissolved insolvent C,evaporated to dryness and heated for x hours at x oC3.2:催化量的反应A(20mL,142mmol)and catalytic amount(a traceamount or two drops)of B were added into a solution of C(4.549g,46.4mmol)in D(120mL)at0 oC3.3:闷罐反应或封管反应A solution of A(x g,x mol)in methanol(x mL)saturated with NH3(or other gas such as:CO,CO2,H2S)was stirred under50Psi at x oC for x hours in a50mL of sealed tube or autoclave.3.4:有气体参与的反应3.4.1:A solution of A(x g,x mol)in methanol(xmL)saturated with HCl was stirred at x℃.3.4.2:Ozone was bubbled into a solution of A(x g,x mol)in MeOH(x mL) at x oC for15minutes.After excess O3was purged by N2,Me2S(x mL)was added at x oC.3.4.3:Gas was bubbled into a solution of A(x g,xmol)and B(x g,x mol) in solvent C(x mL)at x oC for x hours.3.5:混合溶剂参与的反应3.5.1:To a solution of A(x g,x mol)in a mixture of solvent B(mL)and solvent C(x mL)(or a mixed solvent of B and C)was added D(x g,x mol) at x oC,the reaction mixture was allowed to stir(reflux or heat)for x hrs.3.5.2:To a solution of A(x g,x mol)in10:1aqueous acetone(x mL) was added B(x g,x mol)followed by addition of C(x g,x mol),the reaction mixture was allowed to stir(reflux or heat)for x hrs.3.6:分水器分水的反应3.6.1:A(x g,x mol)and B(x g,x mol)in benzene or toluene(x mL)were refluxed for x hours with azeotropical removal of water.3.6.2;A mixture of A,B and TsOH.H2O(56.91g,0.3mol)in toluene(400 mL)was heated to reflux and remove water by Dean-Stark trap.3.7:氢化反应To a solution of A(x g,x mol)in EtOH(x mL)was added Pd-C or Ra-Ni or Pd(OH)2/C(10%,x g)under N2.The suspension was degassed under vacuum and purged with H2several times.3.7.1:The mixture was stirred under H2(x psi)at x℃for x hours.[氢化瓶或高压釜]3.7.2:The mixture was stirred under H2balloon at x℃for x hours.[常压氢化如气球反应]3.7.3:A mixture of A(x g,x mol)and Ra-Ni(x g)in EtOH(x mL)was hydrogenated under50Psi of hydrogen pressure for xhours at room temperature.Part4:反应条件或过程描述4.1:The reaction mixture(solution or suspension)was stirred at5oC for 2hrs and then kept at room temperature(or ambienttemperature)for another2hrs(or overnight)4.2:The reaction mixture(solution or suspension)was refluxed(heated to reflux)or heated at60oC for2hrs(or overnight)4.3:The reaction mixture(solution or suspension)was allowed to reflux (or heat to reflux)for2hrs(or overnight)4.4:The reaction mixture(solution or suspension)was allowed to warm to temperature during2hrs and reflux(or heat toreflux)for2hrs(or overnight)Part5:反应监测5.1:Taking sample from the reaction mixture(solution or suspension)by dropping tube or syringe.After workup,check the reaction via TLC,LC-MS or HPLC etc..(预处理)5.2:反应状态或终点描述5.2.1:The reaction was complete(incomplete or messy)detected (determined or confirmed)by TLC(PE/EtOAc4:1),LC-MS,HPLC or NMR5.2.2:TLC(PE:EtOAc=1:1)or HPLC(107757-088-1)showed or indicated that the reaction was complete.5.2.3:TLC(PE:EtOAc=1:1)or HPLC(107757-088-1)showed the starting material was consumed completely.5.2.4:TLC(PE:EA=1:1)or HPLC(107757-088-1)showed the reaction didn’t work at all or most of starting material was still remained.5.2.5:The starting material was consumed completely,but no desired compound was detected or determined by MS(106657-078-1)or LC-MS (106657-078-1).5.2.6:Several spots were shown on TLC.5.2.7:Only a trace amount of desired compound was detected by MS (106657-078-1)or LC-MS(106657-078-1)or HPLC(106657-078-1)or TLC (PE:EtOAc=1:1).5.2.8:The desired compound could not be isolated,separated or purified by chromatography or prep.HPLC due to poor yield or poor solubility.5.2.9:1H NMR(106675-010-2)or MS confirmed the obtained(or isolated) compound is not the desired compound.The reaction was failed.Part6:反应淬灭6.1:An aqueous solution of A(10mL)was added dropwise into the reaction mixture once the reaction mixture(solution orsuspension)was allowed to warm(or cool)to-5oC or room temperature(ambient temperature).6.2:The hot(or cold)reaction mixture(solution orsuspension)was poured into water(ice water)or poured onto ice.6.3:The reaction mixture(solution or suspension)was concentrated (distilled)under reduced pressure(in vacuum)or evaporated to remove MeOH(THF;DMF etc.)or excess SOCl2(reagent).Then the reaction residue (or the residual)was diluted with solvent and poured into water(ice water) or poured onto ice.Part7:分液提取7.1:The residue was partitioned between ethylacetate(100mL)and1N aq. HCl(50mL).The separated organic layer was washed with water,dried over (Na2SO4or MgSO4)and evaporated to dryness.7.2:After quenching the reaction,the reaction mixture was poured into separatory funnel and separated.7.3:The aqueous layer(or phase)was extracted with organic solvent(40 mL)twice(or X times).The combined organic layers were(or the organic layers were combined and)washed with an aqueous solution of A(50mL) or water and dried over Na2SO4or MgSO4.7.4:The combined aqueous layers were extracted with solvent(40mL)twice (or X times)to remove neutral impurities.The aqueous phase was acidified (or basified)with aqueous HCl(or NaHCO3)till PH=X and extracted with organic solvent.7.5:The combined organic layers were(or theorganic layers were combined and)washed with an aqueous solution of A(50mL)or water and dried over Na2SO4or MgSO4.Part8:浓缩蒸发8.1:After filtration via filter paper or Celitepad,the organic layer (or extract)was concentrated under reduced pressure(or in vacuum)or evaporated to dryness to provide(afford;giveor yield)an oil(or foam) (which solidified on standing)or a white solid.8.2:The organic layer(or extract)was filtered and concentrated under reduced pressure(or in vacuum)or evaporated to dryness to provide (afford or give)A(10g,0.5mole)an oil(or foam)(which solidified on standing)or a white solid.8.3:After removal of solvent by evaporation or concentration,A(10g, 0.5mole)was obtained(or prepared)an oil(orfoam)(which solidified on standing)or a white solid.8.4:The extract in CH2Cl2was evaporated to dryness and then swapped with toluene to remove residual CH2Cl2.Part9:几种常见的后处理描述9.1:The reaction mixture or solution was concentrated to dryness.[适用于反应液不需要quench]9.2:After the reaction mixture was cooled to0℃,the reaction mixture was quenched by addition of xmL of H2O,followed by x mL of15%aqueous NaOH.After being stirred at room temperature for x hour,the solid was removed by filtration(orthe mixture was filtered)through Celite pad to remove by-product).The filtrate was concentrated to dryness to give crude product.[LiAlH4反应的经典后处理]9.3:The mixture was diluted with water(x mL),neutralized with solid K2CO3until no CO2was evolved.[适用于酸性反应液的后处理]9.4:The suspension was filtered through a pad of Celite or silica gel and the pad or filter cake was washed with EtOH(xmL×x).The combined filtrates were concentrated to dryness to give product(x g,x%)as.[适用氢化反应的后处理,或者难于过滤的反应液的后处理,但要注意的是这里需要的是滤液而不是固体才能添加助滤剂]9.5:The reaction mixture was poured into x mL of ice-water carefully and the organic layer or phase was separated.[产物在有机相里]9.6:The reaction mixture was poured into x mL of ice-water carefully and the aqueous phase was washed with Et2O(x mL×x)[产品在水相]and acidified with1NHCl to pH=3.The resulting precipitate was collected by filtration or the resulting solution was extracted with EA(x mL×x).9.7:The reaction mixture was filtered and the filter cake was washed with x mL of solvent,dried in vacuum to give or afford product.[这里需要的是固体而不是滤液]9.8:The reaction mixture was quenched with x mL of saturated aqueous NH4Cl. The resulting solution was extracted with EA(xmL×x).[适用于丁基锂等活泼金属有机物的后处理]9.10:The residue was triturated with ether and filtered to afford a white solid.(磨碎)9.11:The crude product was purified by prep.HPLC to give A as a colorless thick oil which was solidified on standing.(静止固化)9.12:After prep.HPLC purification,the eluent was concentrated or evaporated to remove organic solvents.The residual aqueous solution was lyophilized to give a white solid.(冷冻干燥)9.13:After concentration,the crude product was used directly for the next step without purification.Part10:产品的纯化10.1:The crude product was purified by silica gel chromatography eluted with PE:EtOAc=10:1to give product(x g,x%)as yellow solid.10.2:The crude product was purified by recrystallization(or recrystallized)from x solvent(x mL).10.3:The crude product was distilled in vacuum(xoC,x pressure)to afford pure product(x g,x%)as colorless liquid.10.4:The crude product was pre-purified by column chromatography followed by prep.HPLC purification or re-crystallization to afford pure product.。
SPED_Weekly Reaction Paper 1

Qian ZhangSPED 662Weekly Reaction Paper: Chapter 1Can you imagine you can’t hear anything can’t understand what people say? When I read the chapter one of Educating Deaf Students: From Research to Practice, I suddenly heard the voice of deaf person’s heart and understand how hard to build up the development and the education of a deaf person. There are three important factors in understanding and completing the education of deaf students, which are the “early access to language”, “social interactions”and “diversity in both object- and person-oriented experience”. According to the textbook, “Teachers and researchers, just like their students, always need to be constructing and refining their knowledge.”(10) In my opinions, the best way to educate deaf people is be a friend with them. There is one sentence in Chinese which is “when three people walk together, there will be one of your teacher”. We can’t force deaf people to learnknowledge, but we can study with them, talk with them, walk with them etc. Because parents, teachers have influence with deaf students’education, we need to feel what they feel, think what they think. We must keep doing any kind of research that it can help us to know what’s the best way to close with deaf people, and we can find a better fashion in education of deaf people.Work CitedMarschark, Marc, Harry G. Lang, and John A. cating Deaf Students: From Research to Practice. 1st ed. New York: Oxford University Press,2006.。
ACG奥克兰大学预科化学样卷

Sample Paper AUniversity of Auckland Certificate in Foundation StudiesChemistryTime allowed: 3 hoursTotal: 160 marksQuestion One: Rules and Principles (3 marks)Match the numbers in Column A with the letters in Column B. Place your answer in the table at the bottom of the page. Column A Column BMark the appropriate letters in the table below for the corresponding number.[3]1. Write the full ground state electron configurations using s, p and d notation for a copperatom and a copper(II) ion. (Do not use the noble gas cores.)(a) Cu ___________________________________________________________ [1](b) Cu2+___________________________________________________________ [1]2. Copper(I) oxide undergoes disproportionation when reacting with sulfuric acid. Completethe following equation by writing the chemical formulae of the two missing products.Cu2O + H2SO4 ______________ + ______________ + H2O [1]3. Placing a piece of pure copper in a test-tube containing a small amount of concentratednitric acid will produce a green solution. Give another observation in this experiment._________________________________________________________________________ _______________________________________________________________________ [1]4. The following complex ion has four ligands in its structure and the overall charge is 2+.[Cu(NH3)4]2+(a) Define the term ligand._________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _______________________________________________________________________ [1](b) Give the IUPAC name for the complex ion._______________________________________________________________________ [1](c) State the shape of the complex ion._______________________________________________________________________ [1](d) What is the colour of this complex ion in aqueous solution?_______________________________________________________________________ [1]Electron configurations of four atoms, W, X, Y and Z, are shown below. W, X, Y and Z are not the actual element symbols.1s 2s 2p 3sWXYZ1. Consider the above electron configurations. Answer the following questions using theletters, W, X, Y or Z.(a) An atom of a Group 15 element. ___________(b) An atom with two valence electrons. ___________(c) The atom is able to form a double bond in its diatomic molecule. ___________(d) The most electronegative atom of the four atoms. ___________(e) The largest atom of the four atoms. ___________(f) Write the chemical formula of the compound formed when W react with Z.___________[6]2. (a) Explain why the first ionisation energy of W is higher than that of X._________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _______________________________________________________________________ [2](b) Explain why the first ionisation energy of Y is lower than that of Z._________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _______________________________________________________________________ [2](c) Explain why an X atom is smaller than its anion._________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _______________________________________________________________________ [2]Question Four: Activation Energy (4 marks)The diagram below shows the energy distribution of reactant molecules at a temperature T1.1. Define the term activation energy._________________________________________________________________________ _________________________________________________________________________ _______________________________________________________________________ [1]2. Mark on the energy distribution curve the activation energy, E cat, in the presence of acatalyst. [1]3. Explain, in terms of the energy distribution curve above, how a catalyst speeds up the rate ofreaction._________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _______________________________________________________________________ [1]4. Raising the temperature can also increase the rate of reaction. Sketch on the energydistribution curve above a second curve showing the energy distribution at a highertemperature. Label the curve T2.[1]Question Five: Enthalpy of Formation (8 marks)The table below shows some standard enthalpy of formation data.1. Write the balanced equation with state symbols for the standard enthalpy of formation ofammonium nitrate, ∆f H°(NH4NO3(s))._______________________________________________________________________ [2]2. What is the value of the thermochemical symbol, ∆f H°(C(s))?_______________________________________________________________________ [1]3. Calculate the enthalpy change of the following reaction.2NH4NO3(s) + C(s) → 2N2(g) + 4H2O(g) + CO2(g)[3]4. Calculate the enthalpy change of the following reaction. [Given: ∆vap H°(H2O) = 41 kJ mol-1]2NH4NO3(s) + C(s) → 2N2(g) + 4H2O(l) + CO2(g)[2]Question Six: Bond Enthalpies (6 marks)The following table provides the average bond enthalpies in kJ mol-1.1. Define the term bond enthalpy._________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _______________________________________________________________________ [2]2. Calculate the enthalpy change for the following reaction using the bond enthalpies provided.CH3CH2OH(g) + 3O2(g) → 2CO2(g) + 3H2O(g)[4]Question Seven: Enthalpy of Combustion (4 marks)The diagram below illustrates an approximate method for measuring the enthalpy of combustion of a fuel. The calorimeter used in this apparatus has been simplified as a copper can in the diagram.In an experiment, when 1.00 g of octane was completely burnt in the apparatus shown above, the temperature of 500 g water in the copper can rose from 20.0︒C to 41.5︒C. Calculate the experimental value of the enthalpy of combustion of octane, ∆c H(C8H18(l)).[Given: the specific heat capacity of water = 4.18 J g-1︒C-1][4]Question Eight: Formulae and Isomerism (7 marks)1. (a) What is the empirical formula of compound A?_______________________________________________________________________ [1](b) Compound A exists as a pair of geometric isomers. Draw the structural formula ofthe cis-isomer.[1]2. (a) Write the IUPAC name for compound B._______________________________________________________________________ [1](b) What is the molecular formula of compound B?_______________________________________________________________________ [1] 3. (a) State the type of isomerism between the compounds A and B._______________________________________________________________________ [1](b) Describe a chemical test that can be used to distinguish the compounds A and B.Reagent: __________________________________________________________________ Observations:_________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _______________________________________________________________________ [2]Question Nine: Propanal and Propanone (7 marks)1. (a)To which homologous series does propanal belong?_______________________________________________________________________ [1] (b)Name the functional group present in propanone._______________________________________________________________________ [1] 2. Propanal and propanone can be distinguished by using Tollens’ reagent or Fehling’s solution as propanone is not easily oxidised. (a)What would be observed when propanal reacts with Tollens’ reagent?_______________________________________________________________________ [1] (b)What would be observed when prop anal reacts with Fehling’s solution?_______________________________________________________________________ [1](c) Balance the following two half equations that show the redox reaction between propanal and Tollens’ reagent .[1][1](iii)Write the overall balanced equation for the redox reaction between propanal and Tollens’ reagent.[1]Question Ten: Lewis Structures (8 marks)1. Draw a Lewis diagram for each of the following species.[3]2. Name the molecular shape of oxygen difluoride, F2O._______________________________________________________________________ [1]3. What is the bond angle in a molecule of boron trichloride, BCl3?_______________________________________________________________________ [1] 4. In which one of the three species the central atom shows octet expansion? Circle the correctanswer below.BCl3F2O SO42−[1]5. Is a molecule of boron trichloride, BCl3, polar or non-polar? Explain your answer._________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _______________________________________________________________________ [2]Question Eleven: Graphite (5 marks)Graphite is made up of carbon and a well-known example of giant network solids. The diagram below shows the structure of graphite.1. Explain what is meant by giant network solid?_________________________________________________________________________ _________________________________________________________________________ _______________________________________________________________________ [1]2. In terms of structure and chemical bonding explain the fact that(a) graphite has a very high melting point;_________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _______________________________________________________________________ [2](b) graphite conducts electricity._________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _______________________________________________________________________ [2]Question Twelve: Boiling Points (6 marks)A graph of the boiling points (T b), in Kelvin scale, of the group 16 hydrides and noble gases is shown below.Te5432T bPERIOD NUMBER400K200K1. Krypton has a boiling point of 120 K. Convert 120 K to degree Celsius ( C)._______________________________________________________________________ [1] 2. Explain the rise in boiling points of the noble gases from neon to xenon._________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _______________________________________________________________________ [2] 3. Explain why the boiling point of water is higher than those of the other group 16 hydrides._________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _______________________________________________________________________ [3]Question Thirteen: Organic Products (6 marks)Complete the following equations by giving the organic product in the box provided.1. CH3−C=CH2 HCl∣CH3[1]2. CH3−CH−CH−CH3 conc. H2SO4∣∣CH3 OH reflux[1]major productNH3 in ethanol3. CH3CH2CH2Br[1]4. Br2 and FeBr3[1]5. excess Cl2 / UV lightreflux[1] 6. CH3H+ / MnO4-reflux[1]Question Fourteen: Reaction Routes (9 marks)1. Complete the reaction scheme below by filling in the blank boxes giving the missingreagents [with (aq) or (alc) if necessary].CH2COClCH3CH22NaCH3CH2COO[6]2. Identify the type of reaction that occurs in each case below.(a) From CH3CH2COCl to CH3CH2CONH2:_______________________________________________________________________ [1](b) From CH3CH2CONH2 to CH3CH2COOH :_______________________________________________________________________ [1] 3. Write the IUPAC name for the compound, CH3CH2COOCH3._______________________________________________________________________ [1]Question Fifteen: TNT (6 marks)Benzene can go through a series of reactions to form 2,4,6-trinitrotoluene, better known as TNT. The first step is the alkylation of benzene to form toluene (methylbenzene).1. Complete the reaction by writing in the reactant and catalyst required.CH3[2] The next step is the nitration of toluene with a nitrating mixture.2. Complete the reaction by writing in the condition required and drawing the structure of TNTin the space provided.CH3A + BTNT[2]3. Name or give the chemical formula for the substances A and B in the nitrating mixture._______________________________________________________________________ [1] 4. The second step is also known as an electrophilic substitution reaction. Name or give thechemical formula for the electrophile involved in the reaction._______________________________________________________________________ [1]Question Sixteen: Batteries (6 marks)One type of battery is a lithium button cell. It has an output of 3.00 V and finds applications in heart pacemakers. The overall equation is as follows:Li(s) + MnO2(s) → LiMnO2(s)1. What is the change in oxidation number of lithium in this reaction?From to [1]2. What is the change in oxidation number of manganese in this reaction?From to [1] 3. The reaction occurring at one electrode is:Li → Li+ + e-E°(Li+ / Li) = -3.04 VWrite an ionic half equation for the reaction occurring at the other electrode._______________________________________________________________________ [1] 4. Calculate the standard electrode potential (E°) for the half equation you have provided in theprevious question.[1]5. Which electrode would be connected to the negative terminal in the external circuit?_______________________________________________________________________ [1]6. Suggest a reason that there is no water in the lithium button cell._________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _______________________________________________________________________ [1]Question Seventeen: An Elecrochemical Cell (7 marks)The cell notation summary of an electrochemical cell is given below.Pb(s)∣Pb2+(aq)∣∣MnO4-(aq), Mn2+(aq)∣C(s)1. In the space provided below draw a diagram of the cell as you would construct it in thelaboratory. Label all of the essential components.[3] 2. What colour change would be observed at the cathode during discharging of the cell?________________________________________________________________________ [1] 3. What is the function of a salt bridge in an electrochemical cell?_________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _______________________________________________________________________ [2] 4. A salt bridge may be a salt solution in agar jelly in a U-tube. The salt solution commonlyused is potassium nitrate or potassium chloride. Explain why potassium chloride is not asuitable salt bridge for this cell._________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _______________________________________________________________________ [1]Question Eighteen: Electrode Potentials (6 marks)Use the balanced reduction half equations and the standard reduction potentials listed below to answer the questions that follow.1. Which ion is the strongest oxidising agent listed?_______________________________________________________________________ [1] 2. Which metal is the strongest reducing agent listed?_______________________________________________________________________ [1] 3. Which one of the species in the table above could convert Fe2+(aq) to Fe3+(aq) but notconvert Cl-(aq) into Cl2(aq)?_______________________________________________________________________ [1] 4. Consider an experiment of adding freshly prepared aqueous hydrogen peroxide (H2O2) toaqueous potassium iodide (KI) in a test-tube. Calculate the E︒cell value and then predictwhether or not the reaction will be spontaneous.[3]Question Nineteen: Nitrogen Production (6 marks)Nitrogen can be produced by reacting hydrogen and nitrogen monoxide in the presence of a catalyst at high temperature. The balanced equation is shown below.2H2(g) + 2NO(g) 2H2O(g) + N2(g)1. Predict what would happen to the yield of nitrogen if the overall pressure in the reactionvessel is increased. Explain your answer._________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _______________________________________________________________________ [2]2. Predict what would happen to the yield of nitrogen if the steam produced is condensed towater and then removed from the reaction vessel. Explain your answer._________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _______________________________________________________________________ [2]3. Write the expression of the equilibrium constant (K c) for this reaction.[1]4. If the value of K c is 1028 at 800ºC, what does this imply about the nature of nitrogen?_________________________________________________________________________ _________________________________________________________________________ _______________________________________________________________________ [1]Question Twenty: Hydrogen Sulfide (6 marks)Hydrogen sulfide, H2S, is a foul-smelling compound found in the gases from volcanoes. Hydrogen sulfide is a weak diprotic acid. The first dissociation of H2S in water is given below.H2S(aq) + H2O(l) HS (aq) + H3O+(aq)1. What is meant by the term weak acid?_________________________________________________________________________ _______________________________________________________________________ [1]2. Write the K a expression for the first dissociation of H2S in water.[1]3. Give the conjugate base of H2S._______________________________________________________________________ [1]4. Write an equation for the second dissociation of H2S in water._______________________________________________________________________ [1]5. Apart from water what is the other amphiprotic species in the aqueous solution of H2S?_______________________________________________________________________ [1]6. Comment on the electrical conductivity of the aqueous solution of H2S._________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _______________________________________________________________________ [1]Question Twenty-One: pH (9 marks)Methanoic acid, HCOOH, acts as a monoprotic weak acid when added to water, producing some methanoate ions, HCOO . The pK a value of methanoic acid is given below.pK a(HCOOH) = 3.75, at 25ºC1. (a) Calculate the pH of a 0.500 mol L-1 solution of methanoic acid at 25ºC.[4](b) State the two assumptions involved in your calculation in (a)._________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _______________________________________________________________________ [2]2. Calculate the concentration of hydronium ions in a 0.500 mol L-1 solution of sodiummethanoate, NaHCOO, at 25ºC.[3]Question Twenty-Two: Antacid Tablets (12 marks)Tablets containing magnesium hydroxide can be used as an antacid. Magnesium hydroxide is slightly soluble in water at 25︒C.1. Write the K s expression for magnesium hydroxide in its saturated solution.[1]2. Calculate the solubility of magnesium hydroxide at 25︒C.[Given: K s(Mg(OH)2) = 7.10 ⨯ 10-12, at 25︒C][1] 3. Calculate the concentration of hydroxide ions in a saturated solution of magnesiumhydroxide at 25︒C.[1] 4. Calculate the pH of the saturated solution.[1] 5. If iron(II) ions were added to the saturated solution of magnesium hydroxide at 25︒C, whatwas the minimum concentration of iron(II) ions would a precipitate of iron(II) hydroxideform? [Given: K s(Fe(OH)2) = 4.10 ⨯ 10-15, at 25︒C][2]6. Explain what is meant by common ion effect._________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _______________________________________________________________________ [1]7. Calculate the solubility of magnesium hydroxide in a 0.1 mol L-1 solution of magnesiumchloride at 25︒C.[3]8. Aluminium hydroxide is another active ingredient in most antacids and also slightly solublein water at 25︒C. Would you expect the solubility of aluminium hydroxide in a 0.1 mol L-1solution of sodium hydroxide to be greater than, the same as or lower than that in purewater? Circle the correct answer below.Greater than The same as Lower than Justify your choice._________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _______________________________________________________________________ [2]Question Twenty-Three: Amino Acids (9 marks)The structures of two amino acids alanine and glycine are shown below.1. Classify the amino group in alanine as primary, secondary or tertiary._______________________________________________________________________ [1]2. Alanine exists as a pair of enantiomers containing a chiral centre. Explain the term chiralcentre._________________________________________________________________________ _________________________________________________________________________ _______________________________________________________________________ [1]3. State the difference between a pair of enantiomers in terms of their effect on the plane ofpolarised light._________________________________________________________________________ _________________________________________________________________________ _______________________________________________________________________ [1]4. When two amino acids react together, a dipeptide is formed. In the space provided belowdraw the structures of the two possible dipeptides produced when alanine and glycine react.5. When amino acids undergo condensation polymerisation, a polypeptide is formed. Draw thestructure of the repeating unit of the polypeptide produced using alanine and glycine asmonomers.[1]6. Circle the peptide link in the repeating unit you have drawn above.[1]Amino acids have an acidic functional group and a basic functional group. They normally exist as a zwitterion in aqueous solution.7. Explain the term zwitterion._________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ _______________________________________________________________________ [1]8. Draw the structure of the zwitterion formed when glycine dissolves in water.[1]THE ENDBLANK PAGE。
造纸实验的过程作文

造纸实验的过程作文英文回答:Papermaking Experiment.Materials:Newspaper or other scrap paper.Water.Blender.Screen or mold.Towel or cheesecloth.Heavy object.Instructions:1. Tear the newspaper or scrap paper into small pieces and place them in the blender.2. Add water to the blender, about 2 cups for every 1 cup of paper.3. Blend the mixture until it forms a smooth slurry.4. Pour the slurry into the screen or mold. Use a spoon or other tool to spread the slurry evenly over the screen.5. Carefully lift the screen or mold away from the paper.6. Place the paper on a towel or cheesecloth. Roll up the towel or cheesecloth and press down to remove excess water.7. Unroll the towel or cheesecloth and place the paper on a flat surface.8. Place a heavy object on top of the paper to flatten it.9. Leave the paper to dry overnight or for several hours.Once the paper is dry, you can decorate it as you wish. You can use markers, paint, or glitter to create your own unique design.中文回答:造纸实验。
西方文明史reaction paper之the song of Roland

Actually, I did not finish reading the whole material because David’s requirement was 1-7. But as I wanted to know the result, so I did some search to know about the basic plots of the following story. I learned that this story was mainly to glorify Roland. But here I will just make some comments on the parts of 1-7.In these parts, Blancandrin advised the King Marsilion to pretend to become a Christian and send a large amount of livestocks and treasures to the King Charles.Blancandrin was said to be one of the wisest pagan, but I don’t think he was really wise. He was just a cunning man. His advice could be useful for just a short period, but could never be a permanent one. Because the whole thing was false.The same kind of thing is also very common in our daily life. Anything that is false in essence cannot exist for a long time. All of them will come to an end where they are attacked and broken. It’s just like the situation where you tell a lie and afterwards you have to make up more lies to patch it up. Little by little, the lies pile up and form a vicious circle. So it would be much better to be true at the very first moment and correct the mistake in time.The difficulty for me is that for many times I can understand the meaning of a story but I cannot figure out its deeper significance. Perhaps I should read more and think more to be more profound and critical in my thinking.。
reaction-paper]
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Reaction Paper #1After reading the five short stories, I chose 3 of them I preferred; they are the cask of amontillado, the story of an hour, and the rocking-horse winner. I knew Allan Poe and Lawrence when I was a teenager. I read Allan Poe’s poem, and also Women in love written by Lawrence. Comparing to read poem, I always like reading fictions.For the similarity among the three short stories, first, I noticed their topics are also the symbols for the story. In the first story, the cask of amontillado is the clue of the entire murder. The protagonist found that Fortunato has a wee point which is his pride on his connoisseurship in wine. To let him enter the basement easily, the protagonist told him he bought a cask of amontillado to start his curiosity. Fortunato followed the protagonist to find the Amontillado and want to try the wine, but at last was murdered in the deepest area in the basement. In the story of an hour, from Mrs. Mallard knew her husband’s death to see him back home alive, it is like an-hour-change. She is not that kind of conventional woman who cannot do anything without her husband. On the contrary, she is strong inside to conf ront with the lonely life after her husband’s death; she makes her life full of hope again; she deals with the sorrow alone privately, because she loves her husband after all. Meanwhile, she is read for her new life, her husband came home tiredly. There is a huge drop height between the comfort with her husband’s death and the real life. Maybe, desperately, she died. For the third story, the symbol is, more obvious, therocking horse. The little Paul is a genius who can predict the winner horse of the horse race meeting by riding his rocking-horse. Due to her mother always complain lacking of money and luck, little Paul decided to find the luck and believed that rocking horse can take him to there. But the greed of people destroyed the genius: his uncle found his special ability and take advantage of it to by the most potential horse before the match. While the kind-hearted Paul just want to get the fortune to his mother. The desire for the fortune drove Paul crazy, and his mother and uncle was already beyond crazy. At the end of story, Paul ride on the rocking horse for the last time and got there, he predicted the winner horse again and died. In ancient China, there is a similar story: a genius boy called Zhongyong, he can write poem right away after you chose a topic. His father is extremely proud of him and took him anywhere to sell the poem written by his son but ignored to provide the essential education to his son. Finally, Zhongyong grew up as a normal farmer who cannot even write a poem at all. So, the desire and greed of people can kill everyone who is talented and nice.Also, the three stories have different styles. For the Cask of Amontillado, the author did not tell us who the protagonist is; the only thing we know is that the protagonist will revenge Fortunato because of “thousand injuries of Fortunato.” The entire process of murder is simple and mysterious. The author told us the story as the order of time, but we do not know anything else. The experience of reading is like a steal a glance at the murder case. For the Storyof an Hour, the Author more focused on the mental activities and changes of Mrs. Mallard. Kate Chopin took the omniscient perspective to see through Mrs. Mallard’s mind and describe it for us.Since she is an ultra traditional lady inside, she, in some degree, got freedom from her husband’s death and prepare to enjoy the happy and independent life she would own. She has been looking for ward to “Free! Body and soul free!” for a long time. Unfortunately, her husband came home and ended her dream. She died in desperation. Based on the social background at that time, I think this is a fiction of feminism. And for the Rocking-Horse Winner, this story was written little later than the two I mentioned above. The theme of the story almost has nothing to do with the social background; it is all about unlimited greed and desire come from human nature. At the beginning of the story, the author did not tell us the protagonist’s name but a description about the mother who is always busy in complaining about her unlucky life instead of take care of her children. With the details of the relationship among the few roles was given by the teller, I get to know what kind of boy the Paul is. Paul live in a family where his mother is indifferent to him as a result of concerned about money , while his uncle want to use his genius to make plenty of money. They do not really care about him and what he thought about. After his mother got a mail from the lawyer, she wants more much, so as his uncle. The horrible greed pushed him to the edge of crazy. At the end, it was not under controlled anymore. Hope people can understand what the most valuable is life itself.。
用纸巾做实验作文英语

用纸巾做实验作文英语英文回答:Using paper towels as an experimental material offers numerous possibilities and can provide valuable insights into scientific concepts. Paper towels are commonly used for absorption or cleaning, but they can also be employed in various experiments that explore physical and chemical properties.One fundamental experiment with paper towels involves investigating their absorption capacity. By measuring the mass of a dry paper towel and then immersing it in water, students can calculate the amount of water absorbed. This experiment helps demonstrate the concept of capillary action and can be used to compare the absorbency of different types of paper towels.Another experiment that utilizes paper towels is the chromatography experiment. Chromatography is a techniqueused to separate and identify mixtures of substances. By placing a small sample of a mixture on a paper towel and allowing it to migrate through a solvent, the different components of the mixture can be separated based on their different rates of migration. This experiment can be used to identify dyes, inks, or other substances.Paper towels can also be used to demonstrate the principles of chemical reactions. For example, by placing a drop of hydrochloric acid on a paper towel, students can observe the formation of hydrogen gas. This reaction can be used to illustrate the concept of acid-base reactions and the production of gases.Furthermore, paper towels can be used to explore the effects of temperature on materials. By heating a paper towel in an oven or on a hot plate, students can observe the changes in its physical properties. This experiment can help demonstrate the concepts of thermal expansion and the decomposition of materials.Using paper towels as an experimental material providesa cost-effective and accessible way to conduct scientific investigations. These experiments can help students develop their understanding of various scientific concepts while also honing their experimental skills.中文回答:使用纸巾作为实验材料提供许多可能性,并能对科学概念进行深入探讨。
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Sample of A Reaction paperOf all of the common assumptions that we discussed in class, I think one of the most common is the idea that a children’s text should in some way teach the reader something. We of course talked about the term didactic, and how a didactic book strongly pushes a lesson onto the reader, telling them that they should believe this or that. Many times a reason for that lesson isn’t even given, as though the young person reading the book should just accept that lesson because they are told to, because the other knows better. As I was reading Cat in the Hat by Dr. Seuss, the book I selected for the assignment, I was hoping that it wouldn’t be as didactic as most other children’s books, and that it would be as playful and exciting as I remember as a child. On the last two pages of the book, however, the absent mother returns home, the cat has disappeared, the children are behaving nicely, sitting in chairs, and it is pretty obvious that even though they got into mischief they are still good children after all. Nothing really has changed at the end of the book. Although all sorts of things got played with, and the children broke the rules I am sure they know about (like, “Don’t fly kites in the house”), major boundaries were never crossed.We talked about how the opposite of a didactic book might be an ambiguous book, or a book that encourages the reader to think about issues, to make decisions for themselves. In that kind of book, the author usually wants to the reader to think for her or himself, to understand that some things are difficult, even for adults. The author may present a problem and ask you what you think, or might just never come around to saying exactly what you are supposed to believe. The last page of Cat in the Hat ends with the n arrator saying, referring to the mother, “Should we tell her about it? / Now what SHOULD we do? / Well . . . / What would YOU do / If your mother asked you?” (61). In some ways, this is probably a pretty ambiguous ending. The author asks the reader that if your mother left, if someone wanted you to do what you weren’t supposed to, if you did it anyway, and if you didn’t get caught, then would you tell your mother or father what happened? Most adults wouldn’t tell what happened themselves, but the question is there anyway, and it seems to be really asking children what they believe.But it doesn’t seem really that ambiguous. If the book were really ambiguous it would be breaking the Typical Case Prototype of children’s books, and in almost every other way the book keeps to those prototypes. As Nodelman describes it, children’s books are typically bright, colorful, funny, entertaining, and maybe sometimes rhyming. Children’s books portray children as the way adults typically think of them, as crazy kids who aren’t serious like adults, or innocent angels who would never really do any harm when they play. Dr. Suess portrays typical kids, bored by the rain, wanting to do something wild. Although Seuss’s style is strange, the children even look like the sort of standard white children that appear in most books, the girl in a dress and ribbon in her hair. We saw in class how these children are a lot like the standard one’s in Cassie’s history textbook And although strange things happen in the book – a talking cat, a couple of strange Things, a lot of things getting thrown around –it is the kind of play we come to expect in children’s lives, especially in the sorts of standard things shown on television and in movies.In fact, the children never quite seem to trust the Cat, and they always just sort of watch him play. The children never really do anything that crazy themselves. The Fish, who sounds a lot like an adult, is always there to warn them, and in the end everything gets cleaned up. Of course the book is fun and playful, and is obviously one of the most famous and liked picture books ever made, but it is still pretty straightforward. Cat in the Hat reinforces and demonstrates almost all of the typical assumptions about childhood, and it fulfills all of the typical case prototypes of children’s books. Examining it made me think about how the book might have changed in recent years, especially since children are rarely bored when they are at home any more (with all of the stuff they own to play with). But more than that, it made me think about why we expect all children’s books to be like this, why it is always considered one of the best books for children. Although I like typical children’s books, it makes me also interested in books that don’t do what we expect. The book was written 1957, and in so many ways children’s books have become so incredibly different since then. But in a lot of other ways, some good, some bad, they haven’t changed at all.。