㈠ 化学方面的论文,有中英文对照的,1000字左右的就行
一、溶胶是怎样的概念
胶体从外观上看貌似均匀,与溶液没什么差异,因此胶体常称为溶胶。溶胶与胶体是同一个概念。
二、对淀粉、蛋白质等高分子溶于水形成的分散系,为什么有时称其为溶液,有时又称其为胶体
教材中是按分散质微粒直径的大小来给分散系分类的。淀粉、蛋白质等高分子溶于水形成的分散系可称为胶体。但是判断一种分散系是属于胶体还是溶液,单从分散质微粒直径的大小这一方面来考察,其结论是不全面的,甚至是错误的。正确判断一种分散系是溶液还是胶体,还要看分散质微粒的结构。如果分散质微粒的结构简单,比如是单个的分子或较小聚合度的分子或离子,那么这样的分散系应称为溶液。由于淀粉、蛋白质溶于水后都是以单个分子的形式分散在水中的,因此,尽管这些高分子很大,这些分散系仍应称为溶液。只是因为高分子的大小与胶粒相仿,高分子溶液才具有胶体的一些特性,如扩散慢、不通过半透膜、有丁达尔现象等。化学上常把Fe(OH)3,AgI等难溶于水的物质形成的胶体称为憎液胶体,简称溶胶;而把淀粉、蛋白质等易溶于水的物质形成的分散系称为亲液胶体,更多地是称为高分子溶液。
三、溶液是均一的,胶体也均一吗
憎液溶胶的分散质微粒是由很大数目的分子构成,因此是不均一的;高分子溶液中的分散质微粒是单个的分子,因此是均一的。
四、胶体能在较长时间内稳定存在的原因是什么
憎液溶胶的胶粒带有相同的电荷,由于同性电荷的排斥作用而使憎液胶体可以稳定存在。淀粉、蛋白质等高分子中含有多个极性基团(如—COOH,—OH,—NH2等),可以与水高度溶剂化(高分子表面形成水膜),因此也可较长时间稳定存在。很明显,这两类胶体稳定存在的原因是不同的。
五、溶液中的溶质微粒也作布朗运动吗
胶体微粒在各个方向上都受到分散剂分子的撞击,由于这些作用力不同,所以胶体微粒作布朗运动。溶液中的溶质微粒和分散剂分子大小相仿,因此溶质微粒的运动状况与胶体的胶粒运动状况是有差别的。由于胶体的丁达尔现象,用超显微镜才可以观察到胶粒的布朗运动。溶液无丁达尔现象,因此用超显微镜观察不到溶质微粒的运动状况。
六、凝聚与盐析有何差别
凝聚是憎液(水)胶体的性质,胶体的凝聚过程就是胶粒聚集成较大颗粒的过程。由于憎液(水)胶体的分散质都难溶于水,因此,再采用一般的溶解方法用水来溶解胶体的凝聚物是不可能的,也就是说,胶体的凝聚是不可逆的。盐析实际上就是加入电解质使分散质溶解度减小而使其析出的过程。盐析不是憎液胶体的性质,它是高分子溶液或普通溶液的性质,能发生盐析的分散质都是易溶的,如淀粉溶液、蛋白七、蔗糖溶于水形成的分散系是溶液,为什么在生物课的渗透实验中,蔗糖分子却不能通过半透膜
不同的半透膜,如羊皮纸、动物膀胱膜、玻璃纸等,其细孔的直径是不同的,也就是说,不同的半透膜,其通透性是不一样的。显然,笼统地讲半透膜能使离子或分子通过,而不能使胶体微粒通过是不恰当的。
八、憎液胶体与高分子溶液在性质上有何异同
憎液胶体全面地表现出胶体的特性,高分子溶液则不然。这两种分散系中的分散质微粒都作布朗运动,都有丁达尔现象;憎液胶体有电泳现象,淀粉溶液无电泳现象,而蛋白质溶液则较为复杂;使憎液胶体凝聚的方法有:加入电解质、给胶体加热、加入带相反电荷的胶体,使高分子溶液中的分散质沉淀,主要是破坏高子分与分散剂间的相互作用,如加入大量的电解质也能使淀粉、蛋白质沉淀,这一现象称为盐析,它是可逆的。
九、有没有溶液能产生类似于胶体的电泳现象
由于溶液是均一的,不存在“界面”,因此,给溶液通电不会产生界面移动现象(即一极液面高,另一极液面低),但是有些溶液通电后却可以产生一极溶液颜色加深,另一极溶液颜色变浅的现象。比如,给紫红色KMnO4溶液通电一段时间后,阳极附近溶液的颜色就会变深,阴极附近溶液的颜色就会变浅。这是由于通电后,紫红色的MnO4-向阳极移动,但却不会在阳极放电(MnO4-远比OH-难放电)的缘故。CuSO4溶液就不会产生类似的现象,因为Cu2+会在阴极放电。
十、Fe(OH)3胶体长时间电泳或电压增大,将发生怎样的现象
如果Fe(OH)3胶体长时间电泳或将电泳的电压显着增大,都会在阴极出现凝聚现象,因为不论是长时间电泳还是电压显着增大,都会使阴极附近积聚很多的Fe(OH)3胶粒,大量胶粒的聚集必然会出现凝聚现象。如果电泳电压特别大,还会出现电解水的现象。
质溶液、肥皂的甘油溶液,由于分散质都是易溶的,所以盐析是可逆的。
First, what is the concept of sol
Judging from the appearance of seemingly homogeneous gel, with no difference in the solution, so often referred to as sol-gel. Sol and gel is the same concept.
2, starch, protein and other water-soluble polymer dispersed system formed, why the solution is sometimes called, sometimes also called it as colloidal
Quality of teaching is dispersed particle diameter according to the size of a decentralized system classification. Starch, protein and other polymer dissolved in water to form colloidal dispersion system can be called. But the determination of a colloidal dispersion system or solution are, just from the dispersed particle diameter size of the mass to examine this aspect, the conclusion is incomplete, even wrong. Correct determination of a solution or colloidal dispersion system is, depends on the structure of particle dispersion quality. If the quality of particle dispersion structure as simple as a single molecule or smaller degree of polymerization of the molecules or ions, then it should be called the solution of the decentralized system. As the starch, protein is dissolved in water to form a single molecule dispersed in water, so, even though these polymers large distributed systems should still be called the solution of these. Only because of the size of polymer particles similar, only with the gel polymer solution of some features, such as the proliferation of slow, not through the semipermeable membrane, with Tyndall phenomena. Chemistry often to Fe (OH) 3, AgI and other substances insoluble in water, the formation of colloidal liquid gel called monks, called sol; while the starch, protein and other substances soluble in water, the formation of liquid disperse system as pro- colloid, more is known as the polymer solution.
Third, the solution is homogeneous, uniform gel also do
Hate liquid sol particle dispersion quality by a large number of molecules, it is uneven one; polymer solution, the dispersion of particles is a single molecular mass, and therefore uniform.
4, colloid stability can exist over an extended period because of what
Hate liquid sol particles with the same charge, e to charge repulsion Ershi homosexual hate colloidal solution can exist. Starch, protein and other polymers containing multiple polar groups (such as-COOH,-OH,-NH2, etc.), can be highly solvent and water (molecular water film formed on the surface), so there can be a long time stability . Obviously, these two types of colloidal stability of the reason there are different.
5, solution for Brownian motion of solute particles also do
Colloidal particles in all directions are subject to the impact dispersant molecules, because these forces because of their different colloidal particles as Brownian motion. Solution of solute particles and dispersant molecules are similar in size, so the movement of solute particles and colloidal particles movement situation is different. As the colloidal Tyndall phenomenon, with a super microscope can observe particles of the Brownian motion. Solution without Tyndall phenomenon, not so ultra-microscope, the movement of the solute particles.
6, the difference between condensation and salt
Cohesion is hate liquid (the water) colloidal nature of the condensation process of colloidal particles to larger particles that process. As the monks liquid (water) quality is immune colloidal dispersion of water-soluble, therefore, re-dissolution method commonly used in water to dissolve colloidal aggregates is impossible, that is, the concentration of colloid is not reversible. Electrolyte salt is actually added to its decentralized nature and the solubility decreased precipitation process. Liquid colloidal salt is not the nature of hate, it is common solution polymer solution or the nature of the dispersion of salt can occur are soluble nature, such as starch solution, protein VII, sugar dissolved in water to form the dispersion system is a solution Why infiltration in biology class experiment, but can not be semi-permeable membrane sucrose molecule
Different semi-permeable membrane such as parchment, animal bladder film, cellophane, its pore diameter is different, that is, different semi-permeable membranes, the permeability is not the same. Obviously, generally speaking semi-permeable membrane allows ions or molecules to pass through, without giving colloidal particles through is not appropriate.
8 and hate liquid colloid and polymer solution of the similarities in the nature of
Comprehensive demonstration of monks colloidal solution colloidal properties of polymer solution is not. This decentralized system of two particles in the dispersion quality are as Brownian motion, there Tyndall phenomenon; hate liquid gel with electrophoresis, starch solution without electrophoresis, the protein solution is more complicated; to hate liquid colloid aggregation methods are: adding electrolyte to gel heating, by adding gel with the opposite charge, so that the dispersion of polymer solution quality of precipitation, mainly sub-divided and the destruction of high interaction between dispersant, such as adding a large number of electrolyte also make starch, protein precipitation This phenomenon is known as salting, it is reversible.
9, there is no solution to proce phenomena similar to gel electrophoresis
As the solution is homogeneous, there is no "interface", and therefore to the solution of power does not proce the phenomenon of interface movement (ie a very high surface, another extremely low liquid level), but after powering some of the solution but the solution can generate a very color deepened, and the other pole solution faded color phenomenon. For example, purple KMnO4 solution to power after a period of time, the color of the solution near the anode will become darker in color of the solution near the cathode will be lighter. This is because the power, the purple MnO4-move to the anode, but not in the anode discharge (MnO4-OH-hard than the discharge) of the reason. CuSO4 solution will not proce a similar phenomenon, because Cu2 + in the cathode discharge.
10, Fe (OH) 3 gel electrophoresis time or voltage increases, the phenomenon will happen to
If Fe (OH) 3 gel electrophoresis or electrophoresis time the voltage was increased significantly and there will be condensation phenomena in the cathode, because whether or voltage electrophoresis time was significantly larger accumulation near the cathode will cause a lot of Fe (OH) 3 particles, the aggregation of a large number of particles bound to the phenomenon of condensation. Particularly if the electrophoresis voltage, electrolysis of water is still there.
Quality solution, glycerin soap solution, e to dispersion quality are soluble, so salt is reversible.
㈡ 化学论文怎么写啊
论文一般包括封面、扉页、目录、论文摘要、缩略语表、正文、参考文献、致谢、附录等几个部分。其中正文由前言、材料与方法、结果与分析、讨论等部分组成。
前言
前言应包括研究问题的由来、文献综述、研究目的等基本内容。
研究问题的由来应明确提出论文研究所针对的科学、生产和经济建设的问题,指出研究这些问题的意义。
文献综述主要回顾与所研究课题相关的学科背景,相关领域的研究进展和存在的问题等,是作者对相关文献阅读、消化后的综合、提炼与升华,反映作者对国内外相关进展的了解和理解的程度。因此,文献综述在叙述前人工作的同时,应有自己的看法和观点。不应将文献综述写成前人工作的堆砌,也不应像教科书一样写成知识性介绍。
研究目的是在提出问题和综述文献的基础上,阐述学术思想,提出科学假设或假说,提出论文研究要实现的目标或达到的目的。
材料与方法
详尽列出研究所用材料,如生物材料及拉丁文学名、品种名称、菌株名称,实验材料与课题研究有关的各种特征特性,由实验材料所得到的各种衍生材料、实验群体、世代、数量等,并明确指出各种材料的来源。
详尽描述实验方法,以能将实验材料与实验结果贯通为基础,且他人能按所述的方法进行重复实验。对一些常用的实验方法,可在引用他人文献的基础上,简要加以描述,但对于自己改进或发明的新方法则需要详细说明,指出所用的是他人的方法,还是自己发明的方法,或是在前人基础上的改进及改进的内容等。实验方法还应包括实验设计、田间种植方式、田间管理、试验时间、地点、数据采集(考种)、统计分析方法、所用统计软件、计算机程序等。
结果与分析
详尽陈述课题研究结果,在写作时力求条理清晰,层次分明,做到环环相扣,具有严密的逻辑性,避免重复叙述实验方法,或作过多的讨论。
讨论
讨论是反映作者综合分析、逻辑、思维的能力和水平的重要内容,是在透彻理解结果的基础上,精练地归纳研究的主要结论,指出本研究结果的进步所在和所解决的科学问题,阐明研究结果在理论上和应用上的价值、前景等。讨论中还应指出本研究及其结果所存在的问题、研究工作的不足及进一步开展研究的思路和建议等。讨论内容应注意与前文的研究目的相呼应,要言之有据,避免重复叙述实验结果。鼓励学生以一定的实验证据为基础,进行大胆推论、假设,提出新的学术观点。
参考文献
参考文献紧接正文后面列出,与文中的文献引用一一对应。参考文献排列规则是:中文文献在前,外文文献在后;中文文献按第一作者姓氏拼音字母为序排列,英文及其它西文按第一作者姓氏字母顺序排出;第一作者相同的文献按发表的先后顺序列出,所列的同一第一作者同年内的文献多于一篇时,可在年份后加“a”、“b”等字母予以分别,如“1997a”、“1997b”等;文献作者人数在3人以下的全部列出,超过3人时,列出前3名作者,后面加“等”(“et al”)字以示省略;作者姓名之间用 “,”隔开;姓名一律采用“姓在前名在后”的写法,外国人姓名的名字部分应缩写,并省略缩写点。未公开发表的资料不应列入参考文献,确有引用必要,须在脚注中注明引用。
所有中文参考文献着录格式中的句号和逗号用中文全角状态下的“.”和“,”表示;所有西文参考文献着录格式中的标点符号用西文状态下的符号,后空一格。
结论
结论是对论文主要研究结果、论点的提炼与概括,应准确、简明,完整,有条理,使人看后就能全面了解论文的意义、目的和工作内容。主要阐述自己的创造性工作及所取得的研究成果在本学术领域中的地位、作用和意义。同时,要严格区分自己取得的成果与导师及他人的科研工作成果。在评价自己的工作时,要实事求是,除非有足够的证据表明自己的研究是“首次”的,“领先”的,“填补空白”的,否则应避免使用这些或类似词语。
㈢ 化学方面的英语论文
有机化学英语论文
Abstract
In this work the effects of the microporosity and chemical surfaceof polymeric adsorbents on adsorptive properties of phenol wereinvestigated. Textural parameters of four kinds of polymeric resins namely AB-8 D4006 NKA-II and D16 resin were separately measuredby ASAP 2010. The surface chemistry of these polymeric resins was determined by means of inverse gaschromatography (IGC) and diffusereflectance infrared Fourier transform spectros (DRIFTS). Static equilibrium adsorption experiments were carried out to obtain theisotherms of phenol on the polymeric resins. It was shown that NKA-II and AB-8 resin possessed relatively high BET surface areas andmicropore volumes while D4006 and D16 resin possessed comparatively low BET surface areas and micropore volumes. The results of IGCexperiments revealed that NKA-II resin had extraordinary high specific component of the free energy of adsorption both for polar acetone andbenzene probe and thus extraordinary strong surface polarity compared to the other polymeric resins. It was also found that the isotherm ofphenol on NKA-II was much higher than that on the other polymeric resins e to its strongest surface polarity and largest micropore volumeamong four kinds of resins. These experimental observations indicated that adsorption of phenol on the polymeric resins depended greatly ontheir microporosity and surface chemistry. The well-developed microporosity and the strong surface polarity would improve the adsorptionof phenol on the polymeric resins. 2004 Elsevier B.V. All rights reserved.
Keywords: Polymeric resin; Phenol; Porosity; Surface chemistry; Inverse gas chromatography
㈣ 求一篇化学方面的英文文献
有关化学的,英文版,文献比如研究报告之类的,例如;海水对钢铁腐蚀研究。。越短越好,因为老师要我们把英文翻译成中文
㈤ 求化学英文论文(高分)
实验11 三草酸合铁(Ⅲ)酸钾的制备和组成测定
一,实验目的
1.掌握合成K3Fe[(C2O4)3]·3H2O的基本原理和操作技术;
2.加深对铁(Ⅲ)和铁(Ⅱ)化合物性质的了解;
3.掌握容量分析等基本操作.
二,实验原理
本实验以硫酸亚铁铵为原料,与草酸在酸性溶液中先制得草酸亚铁沉淀,然后再用草酸亚铁在草酸钾和草酸的存在下,以过氧化氢为氧化剂,得到铁(Ⅲ)草酸配合物.主要反应为:
改变溶剂极性并加少量盐析剂,可析出绿色单斜晶体纯的三草酸合铁(Ⅲ)酸钾,通过化学分析确定配离子的组成.用KMnO4标准溶液在酸性介质中滴定测得草酸根的含量.Fe3+ 含量可先用过量锌粉将其还原为Fe2+,然后再用KMnO4标准溶液滴定而测得,其反应式为:
5C2O42-+2MnO4-+16H+ ===10CO2↑+2Mn2+ + 8H2O
5Fe2+ + MnO4- +8H+ ===5Fe3+ + Mn2+ + 4H2O
(NH4)2Fe(SO4)2 + H2C2O4 + 2H2O ===FeC2O4·2H2O↓+ (NH4)2SO4 + H2SO4
2FeC2O4·2H2O + H2O2 + 3K2C2O4 + H2C2O4 ===2K3[Fe(C2O4)3]·3H2O
三,实验仪器与试剂
托盘天平,分析天平,抽滤装置,烧杯(100mL),电炉,移液管(25mL),容量瓶(50mL, 100mL),锥形瓶(250mL).
(NH4)2Fe(SO4)2·6H2O,H2SO4(1mol·L-1),H2C2O4(饱和),K2C2O4(饱和),KCl (A. R),KNO3(300g·L-1),乙醇(95%),乙醇—丙酮混合液(1 : 1),K3[Fe(CN)6] (5%),H2O2 (3%).
四,实验步骤
1.三草酸合铁(Ⅲ)酸钾的制备
① 草酸亚铁的制备: 称取5g硫酸亚铁铵固体放在100mL烧杯中,然后加15mL蒸馏水和5~6滴1mol·L-1 H2SO4,加热溶解后,再加入25mL饱和草酸溶液,加热搅拌至沸,然后迅速搅拌片刻,防止飞溅.停止加热,静置.待黄色晶体FeC2O4·2H2O沉淀后倾析,弃去上层清液,加入20mL蒸馏水洗涤晶体,搅拌并温热,静置,弃去上层清液,即得黄色晶体草酸亚铁.
② 三草酸合铁(Ⅲ)酸钾的制备:往草酸亚铁沉淀中,加入饱和K2C2O4溶液10mL,水浴加热313K,恒温下慢慢滴加3%的H2O2溶液20mL,沉淀转为深棕色.边加边搅拌,加完后将溶液加热至沸,然后加入20mL饱和草酸溶液,沉淀立即溶解,溶液转为绿色.趁热过滤,滤液转入100mL烧杯中,加入95%的乙醇25mL,混匀后冷却,可以看到烧杯底部有晶体析出.为了加快结晶速度,可往其中滴加KNO3溶液.晶体完全析出后,抽滤,用乙醇—丙酮的混合液10mL淋洒滤饼,抽干混合液.固体产品置于一表面皿上,置暗处晾干.称重,计算产率.
①KMnO4溶液的标定
准确称取0.13~0.17gNa2C2O4三份,分别置于250mL锥形瓶中,加水50mL使其溶解,加入10mL 3 mol·L-1H2SO4溶液,在水浴上加热到75~85℃,趁热用待标定的KMnO4溶液滴定,开始时滴定速率应慢,待溶液中产生了Mn2+后, 滴定速率可适当加快,但仍须逐滴加入,滴定至溶液呈现微红色并持续30s内不褪色即为终点.根据每份滴定中Na2C2O4的质量和消耗的KMnO4溶液体积,计算出KMnO4溶液的浓度.
2.三草酸合铁酸钾组成的测定
②草酸根含量的测定: 把制得的K3Fe[(C2O4)3]·3H2O在50-60℃于恒温干燥箱中干燥1h,在干燥器中冷却至室温,精确称取样品约0.2-0.3g,放入250mL锥形瓶中,加入25mL水和5mL 1mol·L-1 H2SO4,用标准0.02000 mol·L-1 KMnO4溶液滴定.滴定时先滴入8mL左右的 KMnO4标准溶液,然后加热到343~358K(不高于358K)直至紫红色消失.再用KMnO4滴定热溶液,直至微红色在30s内不消失.记下消耗KMnO4标准溶液的总体积,计算K3Fe[(C2O4)3]·3H2O中草酸根的质量分数 ,并换算成物质的量.滴定后的溶液保留待用.
③铁含量测定: 在上述滴定过草酸根的保留液中加锌粉还原,至黄色消失.加热3min,使Fe3+ 完全转变为Fe2+,抽滤,用温水洗涤沉淀.滤液转入250mL锥形瓶中,再利用KMnO4溶液滴定至微红色,计算K3Fe[(C2O4)3]中铁的质量分数 ,并换算成物质的量.
结论:在1mol产品中含C2O42- mol,Fe3+ mol,该物质的化学式为 .
五,注意事项
1. 水浴40℃下加热,慢慢滴加H2O2.以防止H2O2分解.
2. 减压过滤要规范.尤其注意在抽滤过程中,勿用水冲洗粘附在烧杯和布氏滤斗上的少量绿色产品,否则,将大大影响产量.
Experiment 11 3 ferrous oxalate (Ⅲ) Determination of potassium in the preparation and composition
One purpose of the experiment
1. Grasp synthesis K3Fe [(C2O4) 3] · 3H2O basic principles and operating techniques;
2. Deepen their understanding of iron (Ⅲ) and iron (Ⅱ) compounds understanding of the nature;
3. Master the basic operations such as capacity analysis.
Second, the experimental principle
In this experiment, ferrous ammonium sulfate as raw material, and oxalic acid in acidic solution of ferrous oxalate precipitation was obtained first, and then use potassium oxalate and ferrous oxalate in the presence of oxalic acid, hydrogen peroxide as the oxidant by iron (Ⅲ) oxalate complex. main reaction is:
Change in solvent polarity and add a small amount of salt agents may precipitate the green monoclinic crystals of pure three-ferrous oxalate (Ⅲ) potassium ions by chemical analysis to determine the composition distribution. Standard solution with KMnO4 in acid medium oxalic acid titrated the content of the root. Fe3 + content can be the first to use excessive zinc reced to Fe2 +, and then use the standard solution of KMnO4 titration and measured, their reaction is:
5C2O42-+2 MnO4-+16 H + === 10CO2 ↑ +2 Mn2 + + 8H2O
5Fe2 + + MnO4-+8 H + === 5Fe3 + + Mn2 + + 4H2O
(NH4) 2Fe (SO4) 2 + H2C2O4 + 2H2O === FeC2O4 · 2H2O ↓ + (NH4) 2SO4 + H2SO4
2FeC2O4 · 2H2O + H2O2 + 3K2C2O4 + H2C2O4 === 2K3 [Fe (C2O4) 3] · 3H2O
Third, experimental equipment and reagents
Pallet scale, analytical balance, filtration devices, beaker (100mL), electric stove, pipette (25mL), volumetric flask (50mL, 100mL), Erlenmeyer flask (250mL).
(NH4) 2Fe (SO4) 2.6 H2O, H2SO4 (1mol · L-1), H2C2O4 (saturated), K2C2O4 (saturated), KCl (A. R), KNO3 (300g · L-1), ethanol (95% ), ethanol - acetone mixture (1: 1), K3 [Fe (CN) 6] (5%), H2O2 (3%).
4, experimental proceres
1. 3 ferrous oxalate (Ⅲ) Preparation of potassium
① Preparation of Ferrous Oxalate: Weigh 5g of solid ammonium ferrous sulfate on the 100mL beaker, then add 15mL of distilled water and 5 to 6 drops of 1mol · L-1 H2SO4, heating dissolved, then add 25mL saturated acid solution, heating and agitating to boiling, then quickly stir a moment, to prevent splashing. stop heating, standing. to be yellow crystals FeC2O4 · 2H2O precipitated decantation, discard supernatant liquid, adding 20mL distilled water crystals, stir and warm, standing, discard supernatant liquid, which was yellow ferrous oxalate crystals.
② Three ferrous oxalate (Ⅲ) Preparation of Potassium: ferrous oxalate to precipitate, by adding saturated K2C2O4 solution 10mL, water bath 313K, constant temperature slowly dropping to 3% H2O2 solution of 20mL, to dark brown precipitate. Edge Bordered stirring, add After the solution was heated to boiling, then add 20mL saturated oxalic acid solution, precipitate immediately dissolved, the solution turns green. hot filtration, the filtrate into 100mL beaker, add 95% ethanol, 25mL, after mixing cooling, you can see the bottom of the beaker and precipitate. In order to accelerate the crystallization rate, which may be dropping to the KNO3 solution. crystal after complete precipitation and filtered, ethanol - acetone mixture of 10mL sprinkling cream cake, drain the mixture. the surface of solid proct in a pan, turning the dark to dry. weighing, calculating the yield.
① KMnO4 solution calibration
Weigh accurately 0.13 ~ 0.17gNa2C2O4 three were placed in 250mL conical flask, add 50mL of water to dissolve, adding 10mL 3 mol · L-1H2SO4 solution in a water bath heated to 75 ~ 85 ℃, hot to be calibrated with the KMnO4 titration, titration rate should start slowly, until the solution had a Mn2 +, the titration rate may be appropriate to speed up, but still drops by to join, titration to the solution and continue to 30s showed reddish discoloration shall not end in. According Each titration Na2C2O4 quality and consumption volume of KMnO4 solution, calculate the concentration of KMnO4 solution.
2. 3 ferrous potassium oxalate determination of the composition of
② oxalate content: the system was the K3Fe [(C2O4) 3] · 3H2O at 50-60 ℃ in temperature oven drying 1h, cooled to room temperature in the dryer, accurately weighed sample of about 0.2-0.3g Put 250mL conical flask, add 25mL of water and 5mL 1mol · L-1 H2SO4, with standard 0.02000 mol · L-1 KMnO4 solution titration. titrated around when the first trickle 8mL KMnO4 standard solution, then heated to 343 ~ 358K (not more than 358K) until the purple disappears. then KMnO4 titration hot solution until the reddish does not disappear within in the 30s. note the total consumption volume of standard solution of KMnO4 calculated K3Fe [(C2O4) 3] · 3H2O oxalate root mass fraction, and converted into amount of substance. titration solution retained after the stand-by.
③ Determination of iron content: in the titration of oxalate retention over adding zinc st rection solution to the yellow color disappears. Heated 3min, so that the complete transformation of Fe3 + Fe2 +, and filtered, washing with warm water sedimentation. Filtrate into 250mL Erlenmeyer flask , re-use KMnO4 titration to reddish calculated K3Fe [(C2O4) 3] content of iron, and converted into amount of substance.
Conclusion: 1mol procts containing C2O42-mol, Fe3 + mol, the substance of the chemical formula.
V. Notes
1. 40 ℃ water bath heating, slowly dropping H2O2. To prevent the H2O2 decomposition.
2. Decompression filter to regulate. Particular attention to the filtration process, do not wash with water in the beaker and Brandt adhesion filter a small amount of green procts on the fight, otherwise, it will greatly affect the output.
㈥ 急~~化学方面英文文献
这样吧,你要的话我可以帮你找一篇,论文会很长的,而且发帖子也不方便,会有乱码,论文都是PDF格式的,你需要的话留下你的邮箱,我给你发邮箱吧。你可以用网络HI联系
㈦ 求化学方面英文论文(文献) 翻译一篇 (附带原文一起)。
去淘宝,有外文文献代查的,知道题目的一篇一元,很快,几分钟即可到货,最好选择卖家是海外的,快些,你懂的
㈧ 帮忙推荐一篇化学相关的英文论文
现在我一见论文俩个字
脑袋都疼 更别说是弄英语的啦,那更是一窍不通
我已经毕业啦
不过当时为了论文的事没少折腾
所以现在...
我写论文的时候怎么写也是不通过
后来实在是挺不住啦
在朋友的介绍下我找到了燕子期刊网的主编雷燕帮我写的
这样才论文才得以通过的
呵呵
他们服务态度很好的
你到网络上搜燕子期刊网就行啦
电话什么的都有你在咨询一下吧
祝你成功
㈨ 英文版论文关于化学的!急!!!!
The Importance of Chemistry in Daily Life
Most people have chosen to write their essay about how chemistry has played an important role in everyday life. I have chosen to ask, how doesn't it play a role in everyday life? The simple fact is that chemistry plays an important role in every person's daily activities from the moment we're born.
So what role does chemistry really play in everyday life? Well, this involvement usually begins first thing each morning. Most people wake up to an alarm or radio. These common household items contain batteries, which make them very chemically dependent. These batteries contain positive and negative electrodes. The positive electrode consists of a carbon rod surrounded by a mixture of carbon and manganese dioxide. The negative electrode is made of zinc. Chemistry plays an important role in the discovery and understanding of materials contained in these and many other common household items. Things like household cleaners and water purification systems are vitally dependent on chemistry. Without chemistry something as simple as scrubbing a toilet without fear of severe burns or small explosions might not be possible.
Next, though it isn?t widely known, chemistry is also heavily involved with the manufacturing of things such as makeup and soap. Each time you bathe you are witnessing chemistry at work. Chemicals such as cetyl alcohol and propylene glycol are typical ingredients in the soap used to wash your hair and skin. Without chemistry, these materials (or combinations of these materials) might be hazardous or might not exist. The chemical coloring agents used in makeup and nail polish would not be possible without an understanding of the chemicals involved.
Almost anything you do ring the course of a normal day involves chemistry in some way. The gas and tires in cars we drive, the makeup we put on our faces, the soaps and cleaners used everyday, burning wood or other fossil fuels, chemistry is all around you each and every day. The associations are practically limitless. So, as you go about your daily activities, remember to thank chemistry. As my teacher always says, remember, "CHEMISTRY IS LIFE!"
㈩ 求一英文 论文 化学方面的~~~
那些数据库啊. 学校都应该买了的. 上本校的图书馆什么的看看4.2. 9-[2-(3-Carboxy-9,10-diphenyl)anthryl]-6-hydroxy-3H-xanthen-3-ones (DPAXs)
The most widely used 1O2 trap is 9,10-diphenylanthracene (DPA), which reacts rapidly and
specifically with 1O2 to form a thermostable endoperoxide at a rate of k =1.3106 M1 s1.
The decrease in absorbance at 355 nm is used as a measure of the formation of the endoperoxide.
However, DPA derivatives are not very sensitive probes because the detection is based on the
measurement of absorbance [79].
Umezaka et al. [79] fused DPA with a fluorophore (fluorescein) aiming to associate the first’s
reactive characteristics with the second’s fluorescent characteristics. Fluorescein was chosen as
fluorophore since it has a high fluorescence quantum yield in aqueous solution and is able to be
excited at long wavelength. From this fusion resulted 9-[2-(3-carboxy-9,10-diphenyl)anthryl]-6-
hydroxy-3H-xanthen-3-ones (DPAXs) (Fig. 11) [79]. Thus, DPAXs were the first chemical traps
for 1O2 that permitted fluorescence detection. They react with 1O2 to proce DPAX
endoperoxides (DPAX-EPs) (Fig. 11). DPAXs themselves scarcely fluoresce, while DPAXEPs
are strongly fluorescent. The mechanism accounting for the diminution of fluorescence in
DPAXs and its enhancement in DPAX-EPs remain unclear [79].
The fluorescence intensity of fluorescein derivatives is known to be decreased under acidic
conditions as a consequence of the protonation of the phenoxide oxygen atom. In order to
stabilize the fluorescence intensity at physiological pH, electron-withdrawing groups wereincorporated at the 2- and 7-positions of the xanthene chromophore, leading to Cl (DPAX-2) and
F (DPAX-3) (Fig. 11). This modification lowered the pKa value of the phenolic oxygen atom
[79].
DPAX-2 was used to detect the proction of 1O2 from two different generation systems: the
MoO4
2/H2O2 system and the 3-(4-methyl-1-naphthy)propionic acid endoperoxide (EP-1)
system, which act at different pH values (10.5 and 7.4, respectively). In both cases an increase
of the probe’s fluorescence was verified when in contact with the generating system. These
results confirmed DPAXs’ advantage when detecting 1O2 in neutral or basic aqueous solutions
[79]. The behaviour of this probe towards H2O2, !NO and O2 ! was also studied, but no change in
the intensity of the fluorescence was observed for any of these reactive species. These facts
corroborate the specificity of this probe for 1O2 [79].
The detection of 1O2 in biological samples was also investigated. With this purpose, DPAX-2
diacetate (DPAX-2-DA) was prepared, since it was considered to be more permeable to cells.
DPAX-2-DA is hydrolysed by intracellular esterases to generate DPAX-2. Both DPAX-2 and
DPAX-2DA were tested and compared in the same assay systems. However, cells were stained
similarly in both cases. This observation probably means that DPAX-2 itself is also membranepermeable