化学趣味实验英语毕业论文

impossible between members of different species because genitals of males and females are structurally incompatible or because molecules on the surfaces of sperm and egg fail to bind. A final type of prezygotic mechanism is temporal isolation, in which time-related environmental cues that trigger reproductive processes are different for related species.有时，产生前合子隔离的差异涉及了隔离机制。即，由于生殖器结构不匹配或精卵分子表面不结合而使不同种群成员间不能自然结合。最后一类前合子机制是暂时隔离，与时间有关的环境因素触发了相关物种的不同繁殖过程。

许多已知的冰阶段表现出了质子订购 转型，例如从质子无序 六角冰（星期四）以质子下令冰十一.1最近，两个 新质子命令冰阶段（十三和十四）已reported2 有关冰第五和第十二， 若干冰 阶段并不简单，这解释了为什么直到最近， 只有一个新的冰阶段已经发现在过去20 特别是，排列形式的冰可能难以孤立内 该实验室因为动力学障碍分子轮换 是重要的低仿真提供了一个 辅助方法，在其中的影响，压力，温度， 和配置可以名义上控制十分精确，以 允许系统测绘阶段的 Verity的任何模拟方法取决于其生育能力 不同的国家分相挑战理论， 我们最近进行了一项双盲试验预测质子有序 形式的冰第十二称为冰十四。 虽然每个冰氧原子必须四面体协调员 化（在一个完美的网格） ，氢原子可能是无序的。 安排的质子在一个冰结构的确定 由贝尔纳福勒冰rules4其中规定： （ 1 ）必须有 两个氢原子毗邻每个氧气和（ 2 ）必须有 只有一个氢每表明，氢 任何冰阶段大约有（ 3 / 2 ）不适用何种方式 氢原子可安排，并建议所有可能的 结构的某一阶段是 ，存在 质子命令无效这一阶段质子 命令阶段有不同的特性从无序母公司 阶段，例如，冰七可以转化为质子下令冰 八的相关变化，晶胞参数和密度。

Purpose: See mold (mold) the circumstances under which grow the fastest Experimental materials: two slices of bread, water, a paper bag Experimental methods: (1) Take 1 slice of bread, tear (slice) in two, one on the dry environment, a sprinkle of water on top (2) and then take a piece of bread, torn in half, one in a dark environment (in a paper bag) and one on the glare Results: top watering bread mold grow faster on On the paper bag of bread mold grow faster on Experimental results: mold in damp dark environment grow faster

Cultivation and preparation of potassium aluminum sulfate crystalsFirst, the purpose of the experiment1 . Learn from the principle of the preparation of aluminum and aluminum potassium sulfate process ;2 . Further understanding of Al and Al (OH) 3 sexes ;3 . Principles and methods of learning in the crystals from the , the experimental principleAluminum sulfate with an alkali metal sulfate (K2SO4) and potassium aluminum sulfate and generated potassium sulfate (K2SO4 · Al2 (SO4) H2O) , commonly known as alum, which is a colorless crystals , soluble in water and hydrolysis of Al (OH) 3 gel precipitation. It has strong adsorption properties is an important aluminum industry, can be used as purifying agent , paper filling agent for many purposes .The experiment was dissolved in sodium hydroxide solution using the aluminum metal , aluminum hydroxy generated four soluble sodium aluminum impurities in the remaining insoluble impurities removed by filtration . H2SO4 followed by adjusting the pH of the solution was 8-9 , . with Al (OH) 3 precipitate , after separation , the precipitate was added H2SO4 , that the conversion of 3 Al2 (SO4) 3 Al (OH), then formed Al2 (SO4) 3 crystals, Al2 (SO4) 3 K2SO4 crystals and crystals were saturated solution , after mixing, have generated alum . About the reaction is as follows :2Al + 2NaOH + 6H2O === 2Na [Al (OH) 4] + 3H2[Al (OH) 4] - + H + === Al (OH) 3 + H2O2Al (OH) 3 + 3H2SO4 === Al2 (SO4) 3 + 6H2OAl2 (SO4) 3 + K2SO4 + 24H2O === K2SO4 · Al2 (SO4) H2OAlum monocrystalline culture : When there K2SO4 · Al2 (SO4) H2O after precipitation of crystals , the crystal was filtered , structured as a selected seed crystals in the filtrate, and covered with a watch glass , allowing the natural evaporation of the solution , crystallization will gradually grow to become a large single crystal , single crystals with octahedral crystal form . The seed crystal to be grown as a single crystal , it is important not to change the temperature of the solution is so large that the water solution was slowly evaporated. Also to be grown crystals can also be generated on the crystal system of nylon rope , suspended in solution. Such crystal growth rate is not affected in all respects , to generate a more regular crystals .Third, experimental suppliesInstruments and Materials : beakers, electronic scales, Buchner funnel , evaporating dish , alcohol lamp , tripod, asbestos network , matches, glass funnel , graduated cylinder , filter paper , pH test strips, nylon : Al crumbs (CP), NaOH (CP), K2SO4 (CP), H2SO4 (3mol · L-1, 1:1), BaCl2 ( mol · L-1).Fourth, the experimental procedure1 . Al (OH) 3 is generatedWeigh g of solid NaOH , placed in 200mL beaker, add 30mL distilled water . Weigh 1 g of aluminum shavings in batches into the solution ( violent reaction against spills , should be carried out in a fume hood ) , to no more bubbles , and the reaction is completed, then add distilled water to bring the volume to approximately 40mL , filtration . The filtrate was transferred to 200mL beaker and heated to boiling , under continuous stirring , a solution of 3mol · L-1H2SO4, the pH of the solution is 8-9 , and stirring was continued for several minutes to boil , then suction filtered and the precipitate washed with boiling water until the pH value of the washing liquid is reduced to about 7 . Preparation of Al2 (SO4) 3 inThe resulting Al (OH) 3 into a beaker with constant stirring , was added 1:1 H2SO4, and water bath . When the solution becomes clear, stop the addition of sulfuric acid to give Al2 (SO4) 3 solution . The solution was concentrated to one half of the original volume , removed, cooled to room temperature and washed with water until crystallization was complete, filtered, the crystals were blotted dry with filter paper and weighed .3 . Preparation and training of large crystals of alumAluminum sulfate crystals weighed into a small beaker, dubbed a saturated solution at room temperature. Another Weigh K2SO4 solid , also dubbed the same volume of a saturated solution , and then an equal volume of a saturated solution of the two -phase mixture, stirring well. After standing , alum crystals will be precipitated. Filtration , elected structured as a seed , on the filtrate , cover the surface of the pan, allow the solution to natural evaporation, crystallization will gradually grow to become a large single crystal , single crystals with octahedral crystal form .In order to generate a large single crystal seed , it is important not to change the temperature of the solution is so large that the water solution was slowly evaporated. To generate large crystal , the crystal can also be generated on the system nylon rope suspended in the solution. Thus in all aspects of the crystal growth rate is not affected .

Aluminum potassium sulfate preparation and crystal growthOne, the purpose of the experiment1 understand the principle and process of producing aluminum sulfate;2 further understanding of the Al and Al (OH) 3 sexes;3 education principles and methods of crystals from , the experimental principleThe sulfate aluminum with alkali metal (K2SO4) forming aluminum potassium sulfate potassium sulfate (K2SO4 · Al2 (SO4) 3 · 24H2O) commonly known as alum, it is a kind of colorless crystals, Yi Rong in the water, and the hydrolysis of Al (OH) 3 casse. It has a strong absorption performance, aluminum salt industry is important, as water purifying agent, filling agent in papermaking etc..This experiment using aluminum dissolved in sodium hydroxide solution, four hydroxy aluminum acid sodium production of soluble metal aluminum, otherimpurities are insoluble, filter to remove impurities. Then using H2SO4 to regulate the pH value of the solution for 8-9, namely Al (OH) 3 precipitate,separation, adding H2SO4 in the precipitation, the Al (OH) 3 into Al2 (SO4) 3,and then made into Al2 (SO4) 3 crystals, Al2 (SO4) 3 crystal and K2SO4 crystalrespectively into saturated solution, mixing with alum generated. The reaction is as follows:2Al + 2NaOH + 6H2O = 2Na[Al (OH) 4] + 3H2[Al (OH) 4]+ H+ = Al (OH) 3 + H2O2Al (OH) 3 + 3H2SO4 = Al2 (SO4) 3 + 6H2OAl2 (SO4) 3 + K2SO4 + 24H2O = K2SO4 · Al2 (SO4) 3 · 24H2OCultivation of alum crystal: when there is K2SO4 · Al2 (SO4) 3 · 24H2O crystal precipitation, filtering to obtain crystal, choose structured as a seed, put in the filtrate, the upper dish, let the solution of natural evaporation, crystallization will gradually grow up, become a large single crystal, crystal has eight surface morphology. In order to make the seeds grow large single crystal, it is important not to solution temperature change is too big, make water slow evaporation. In addition to grow large crystals, crystal system can also be generated with the nylon rope, suspended in solution. Such crystals in the growth rate is not affected, the crystals formed more , experimental equipmentApparatus and materials: beaker, electronic scales, funnel, the evaporating dish,alcohol lamp, three tripod, asbestos, matches, glass funnel, cylinder, filter paper,pH paper, nylon : Al chip (), NaOH (), K2SO4 (), H2SO4 (3mol · L - 1, 1:1),BaCl2 ( mol · L - 1).Four, the experimental (OH) 3 generationTake grams of NaOH solid, into a 200mL beaker, add 30mL distilled water solution. Take 1 grams of aluminum scrap, in batches into the solution (reaction,prevent spills, should be carried out in a fume hood), to no longer have bubbles,indicating the reaction is completed, and then adding distilled water, the volume is about 40mL, filtration. The filtrate into a 200mL beaker, heated to boiling, withcontinuous stirring, add 3mol · L - 1H2SO4, the solution of pH 8 - 9, continue to stir boiled a few minutes, and then filtration, washing and precipitation with boiling water, until the washing liquid pH value reduced to about 7, (SO4) 3 preparationThe prepared Al (OH) 3 into the beaker, under continuous stirring, adding 1:1,H2SO4, and water bath heating. When the solution became clear, stop adding sulfuric acid, Al2 (SO4) 3 solution. The concentrated solution for the 1/2 of the original volume, removed, water cooling to room temperature, the crystallization,filtration, the crystal blot with the filter paper, and crystal 3 alum systemThe weighing of the aluminum sulfate crystal is arranged on the small beaker,with saturated solution at room temperature. The other weigh K2SO4 solid, alsowith the same volume of saturated solution, and then an equal volume of twosaturated solution phase mixing, stirring evenly. After placement, there will bealum crystal precipitation. Select the filter, structured as a seed, put in thefiltrate, the upper dish, let the solution of natural evaporation, crystallization will gradually grow up, become a large single crystal, crystal has eight order to make the seed generation of large single crystal, it is important not tosolution temperature change is too big, make water slow evaporation. To generate a large crystal, crystal system can also be generated with the nylon rope, suspended in solution. Such crystals in the growth rate is not affected.

Purpose:See mold (mold) the circumstances under which grow the fastestExperimental materials: two slices of bread, water, a paper bagExperimental methods: (1) Take 1 slice of bread, tear (slice) in two, one on the dry environment, a sprinkle of water on top(2) and then take a piece of bread, torn in half, one in a dark environment (in a paper bag) and one on the glareResults: top watering bread mold grow faster onOn the paper bag of bread mold grow faster onExperimental results: mold in damp dark environment grow faster