全國中小學科展

化學

很錳的顏色

高二上學期化學第一章,就討論到電子組態及原子光譜,雖然課本上有美麗的光譜插圖,但是觀念還是覺得十分抽象。所以老師為了提高我們學習的興趣,在實驗課中教我們自製簡易分光器,實際去觀賞各種光源及有色溶液的光譜,觀賞過程我們發現下列的問題:(1)為何一般離子是帶狀光譜,而MnO4- 光譜卻像線光譜?(2)MnO4- (深紫)和Mn2+(幾近無色),兩者顏色差異很大。是否與Mn 離子是否單獨存在有關係?(3)而另外CrO42- (黃)、Cr2O72- (橙)和Cr3+(深藍色),三者顏色差異,是否與MnO4- 和Mn2+原因類似?為了尋找這些答案,於是開始了這個題目研究的過程。這期間我們花了很多時間與方法,嘗試將肉眼觀察到的影像,在自設的簡單暗房中,將光柵卡在數位相機的鏡頭前,以腳架或翻拍架拍攝下來。另外我們也應用到高三上學期平衡常數測定實驗中比色法的觀念,以及物理學上單狹縫繞射的觀念,使課本中的理論與實驗研究相互結合!最後我們藉分光光譜儀測定各有色溶液的可見光吸收光譜,再去定量分析這些有色溶液的顏色深淺,並查閱相關的文獻資料。最後發現MnO4-應該是一種電荷傳遞的遷移,所引起特別深顏色的現象。 至於CrO42- 、Cr2O72- 和Cr3+三者顏色比較上是否和MnO4- 和Mn2+一樣的情形?我們推測應該也是如此!初見Cr3+有很深的顏色時,的確嚇了一跳,不過最後我們還是從它們的可見光吸收光譜中發現: CrO42- 、Cr2O72- 在λmax 的吸光度比Cr3+還要大!但是為何肉眼觀察到的Cr3+顏色會比較深?那是因為我們視覺上對藍綠色比較敏感的緣故!請參考表一。 We have discussed some electronic configurations and atomic spectrums in chemistry class. Although there were a few beautiful spectrums in textbook , but it’s difficult to understand. So we made a simple spectroscope by ourselves to observe spectrums of different light source and color solution . After some observation we have found some problems below : (1)Why the spectrum of color solution is band spectrum , but the spectrum of permanganate ion (MnO4- ) like line spectrum? (2)MnO4- (deep purple)and Mn2+(pink), their color are different very much. Is it because of the lone existence and binding with oxygen atom of manganese ion? (3)Additionally CrO42- (yellow)、Cr2O72- (orange)、Cr3+(deep blue),Are their color’s difference same as MnO4- and Mn2+? In order to solve it , we started to do the reasrech. We tested different methods much time to record . Finally , We found a good method . That’s placed a grating in front of the digital camera len to take single slit diffraction spectrum pictures in the dark space. Additionally we used spectrophotometer to measure the visible light absorption spectrum. We compared and matched with single slit diffraction spectrums and visible light absorption spectrums. Then we found the intense color of MnO4- due to charge transfer in reference book. How about color’s difference between CrO42- 、Cr2O72- 、Cr3+group and MnO4、 Mn2+ group? We guess they had the same result . We can find the λmax of CrO42- 、Cr2O72- is larger than Cr3+ from the absorption spectrum. But the observation from naked eyes was inverse . This is owing to our vision is more sensitive to blue color. Refer Table 1.

A Novel Approach of Photogenerated Electron-hole Pairs Transfer in CuFeO2-Bi20TiO32 Photocatalytic Water Splitting Combined with a PEM Fuel Cells

氣候暖化是一個地球目前正面臨的一大議題,造成地球暖化的主要原因是長期大量使用的化石性燃料所產生的二氧化碳等溫室氣體因此尋找一個替代性的能源是一個當今十分重要的問題。本研究將可見光光觸媒Bi20TiO32、CuFeO2粉體及鐵絲網懸浮於內照式光觸媒觸媒反應器內,當受激發之光觸媒粉體與鐵絲網發生碰撞,則可使光生電子-電洞經金屬-半導體異相介面傳遞至另一光觸媒之活性位置,藉此有效地分離光生電子-電洞而提高光觸媒水分解之產氫速率。本研究發現,利用此一光生電子-電洞傳遞途徑,在293 K下CuFeO2之光觸媒活性可達8.38 mL H2/min‧g。然而,本研究中光觸媒水分解之產氫速率在沒有氣體壓縮器的協助下,未能有效地驅動質子交換膜燃料電池。本研究亦探討質子交換膜燃料電池之最佳化條件,發現在333 K下,以100 mL/min純氫作為進料,可使質子交換膜燃料電池在0.6 V之操作電壓下,輸出0.78 W之電能。在未來,將本研究發展之光觸媒反應系統與質子交換膜燃料電池結合成光電能轉換系統,則可能夠在日常生活中有效地被運用。

“碘化鋅”產率變變變---溶劑對產率的影響

The research mainly discuss the influence on the rate of zinc iodine with different solution as catalytic agent. We use water, acid water, ethanol methanol acid ethanol, and acid methanol and so on as different solution to participate in the process of an equation: Zn+I2 → ZnI2 to work out the variation of the product's amount. Besides, we also change the proportion of Zinc and Iodine to discuss the difference between the proportion of reactant and the product's amount. The result shows that the product of this equation is ZnI2 not Zn(I3)2. Ethanol and methanol have the same effect as water to accelerate the process of the equation. We find out that this reaction get higher product's amount in acid condition. Also, put the mass Zinc with the mass iodine can get higher product's amount, Furthermore, acid in specific range (0.01M—1.00M), the denser the acid is, the higher product's amount we get. But how the water as catalytic agent work in the reaction is the direction we can research deeply in the days to come. 鋅和碘作用生成碘化鋅的反應,是用水作為催化劑,然而一小滴水卻使這個反應劇烈進 行,我們嘗試了多種和水具有相同作用的催化劑,由於反應時間極短不易測量,我們考慮由 產率部分著手,讓原本只需一小滴的水〈催化劑〉改為此反應的溶劑,計算其產率的變化。 實驗分為三部分,第一部份先是改變不同的溶劑,讓鋅和碘在不同溶劑〈水、酸化水、乙醇、酸化乙醇、甲醇、酸化甲醇〉下反應,計算出產率的變化,我們發現在酸中的產率的確較不加酸者來得高。第二部分我們改變加入鋅和碘的量,改變鋅和碘的比例,讓鋅由過量到成為此反應的限量試劑,觀察其產率的變化,我們發現碘作為限量試劑較鋅作為限量試劑的產率高。由於此反應在酸中產率較高,但酸的濃度高低是否又會影響產率呢?我們繼續第三部分的實驗,改變酸的濃度,讓此反應在不同的酸化水濃度的溶劑下反應,討論產率和酸濃度的關係,我們發現在一定範圍內〈0.01M~0.5M〉,酸的濃度越高,產率亦越高。 實驗方法是將鋅和碘置入同一試管中反應,並使其在不同溶劑中反應,接著離心,將碘化鋅水溶液與未反應完的反應物分離,將所得的碘化鋅水溶液使用結晶法得到碘化鋅晶體,秤重並計算其產率。

聚苯胺導電高分子在鐵系金屬防蝕上的應用與研究

聚苯胺導電高分子的發展蓬勃迅速,其應用也愈趨廣泛,金屬防蝕為其可能應用之一。台灣四面環海,工業發達,造成金屬腐蝕損害嚴重。本文為探討聚苯胺導電高分子在鐵系金屬防蝕上之應用,針對以下各點進行研究: ( 1)探討導電高分子聚苯胺性質與合成方法(2)探討聚苯胺導電原理(3)測試不同腐蝕條件下聚苯胺的防蝕效果(4)探討聚苯胺防蝕原理(5)各種氧化還原態聚苯胺防蝕效果之比較。實驗結果顯示塗布聚苯胺與未塗布聚苯胺之鐵系金屬(生鐵、不鏽鋼、鍍鋅鐵)在 3 %氯化鈉、 0 . 5M 鹽酸、1M 鹽酸溶液中之腐蝕狀況,以鹼式中問氧化態聚苯胺( Emeraldine base 。)最具防蝕效果。聚苯胺防蝕機構包含阻隔防護、腐蝕抑制劑、陽極保護、惰性化、形成保護性氧化物薄膜、阻礙離子擴散速率、電化學介面遷移等機構 ·The development and application of the conducting polymer polyaniline is getting prosperous and popular. One of the applications is corrosion protection. Because Taiwan is surrounded by sea and the pollution of industry is more and more serious than before the damage of corrosion is greater and should be properly controlled. In this paper, the authors attempted to study the effect of the corrosion protection of polyaniline in ferrous metal. This study could be divided into four parts: (1) the study of the property and synthesis methods for the conducting polymer polyaniline, (2) the conduction theory of the polymer polyaniline, (3) The corrosion protection effects of the polymer polyaniline under different corrosion situations, (4) the corrosion protection theory of the polymer polyaniline, and (5) the comparison of the corrosion protection effects of various polymer polyanilines. According to the experimental results the Erneraldine-based polyaniline gets the best corrosion protection effect. The mechanism of corrosion protection may be the result of the following ones: barrier protection, corrosion inhibitor, anode protection, innobeling, chemical active layer. inhibition of diffusion rate, and the shift of electrochemical interface.

直接乙醇燃料電池之觸媒層研究

直接乙醇燃料電池以酒精與氧氣透過氧化還原反應產生電能,但化學反應緩慢,需利用觸媒以增加其速率。本實驗目的在於盡可能找出一個表現最佳的觸媒。本實驗利用活性碳粉作為觸媒(鉑、錫)的載體,以酸性(HNO3)與鹼性(NaOH)環境分別處理碳粉,再以含浸法與多元醇含浸法將觸媒還原。我們得到以HNO3 處理的碳粉無法保有原碳粉的型態,較利用NaOH 處理為差。在觸媒製備方面,多元醇含浸法還原效果比含浸法可得到較小的觸媒尺寸,在本實驗中,溶液中鉑與加入的碳粉重量比為3:7 時,可得到最大的反應面積。此外,當鉑與錫原子數比為4:1 時,可得到最大的乙醇氧化電流。Direct ethanol fuel cell is a kind of power source which generates electrical power by a redox reaction involving ethanol fuel and oxygen. However, this reaction takes place slowly; therefore, catalyst is needed to improve its activity. The goal of this project is to get an optimize catalysts ratio to obtain the best catalyst activity. Activated carbon is used as the support of catalyst (platinum and tin) particles in this project, which is pre-treated in acid (HNO3) and alkaline (NaOH) solutions respectively. Then, the precursor is reduced by impregnation and EG-impregnation. We learned that activated carbon pre-treated with NaOH activates better than which pre-treated with HNO3 because the latter bear less resemblance than the former. As for the catalyst, the results of EG-impregnation show smaller size of catalyst particles than those of impregnation. In this project, when the ratio of the weight of platinum and activated carbon added into the solution is 3:7, we can get the largest surface area. In addition, when the ratio of the amount of platinum and tin atoms is 4:1, we can get the largest current of ethanol oxidation.

聚苯胺導電高分子二次電池之研製及性能研究

塑膠一向被認為絕緣體。但Heeger,MacDiarmid,以及Shirakawa證實,塑膠可以被改製成電的良導體。這須在高分子合成的過程中,使碳鏈呈現單、雙鍵交錯排列情形。此外,高分子也須加以摻雜(doped),換言之,電子必須在氧化過程中被移除或在還原過程中被加進聚合物。電子移除所留下的電洞,或新加進的電子則可自由在分子鏈上移動,形成導電性。我們所要製備的導電高分子二次電池就是由這個原理完成的。所謂的二次電池(Secondary Cell)簡單的定義就是「可反覆充電、放電,循環使用的電池」,我們將會將其與市售電池比較,並改良出合適商品化的高分子二次電池。我們將以聚苯胺做為我們電池的正極,並用鋅片(原本我們要用鋰金屬的,但其再空氣中即易氧化,因此改採鋅)做為負極,製成一聚苯胺二次電池。The plastics is thought to be a insulator, but Heeger, MacDiarmid, and Shirakawa had proved that conductivity of plastics can be improved by doping other media. The conjugated polymers such as polyacetylene、polyaniline have the interlaced single-double bonds that electrons can move from one side to another side caused the production of electric currents. The purpose of this study is try to study the application of the conjugated polymer polyaniline to make a secondary battery. First, we use the chemical and electrochemical method to compose the polyaniline. Then we test the conductivity of the produced polyaniline and test the current and electrical potential of the polymer battery. The battery that we made from our laboratory has the electric potential about 0.5 volts and the electric current is greater than 50 microamperes. Finally, we also try to use the lithium as cathode to improve the performance of the polyaniline battery.

誰能比我更善變???~ 釩鎵磷酸鹽的合成及其結構鑑定

This research tries to find out how changes of weight or proportion of a reactor would affect the type and structure of a crystal. In the experiment, the Hydrothermal reaction was adopted to conduct the syntheses of Vanadium-substituted Gallium Phosphates and try to pick up the single crystal to collect data with SXRD for further illustrating the crystal structure with diamond software to know well its nature. The research result finds out a new type of crystal unseen in the existing literature produced because of the weight changes of C3H10N2, therefore the weight change of a reactor may affect the structure of crystal significantly. In the future, it is expectation that comparison among structures of other Vanadium-Substituted Gallium Phosphates can be made, and the properties of this compound can be measured, and try to find out a brand new type of structure for new exploration by changing the initial reagent. 本研究係透過改變化合物所添加之反應物的比例,以了解反應物比例的改變對晶體的型態與結構的影響。實驗採用中溫水熱反應來從事金屬釩鎵磷酸鹽的合成。並挑取單晶,以X-ray 繞射儀進行數據收集,再以diamond 軟體繪出晶體的結構圖,且進一步得知其性質。研究結果發現,經改變丙二胺的量後,產生不同於文獻上的新化合物,可知改變所加反應物的比例,對於晶體結構有相當大的影響。未來可朝向與其他的釩鎵磷酸鹽做結構上的比較、對此化合物做更進一步的性質測量、改變起始試劑測試,進而得到更新穎的結構形式等部分進行探究。

多重電極並聯情況下交、直流電解水的比較研究

The temperature of the water was commonly higher and both of electrodes were oxidized during electrolysis by using alternating current, but the above happenings were only found at the positive electrode by using direct current. It can be explained by the principle of the microwave stove. The exchange of the current causes the water molecules to release heat. The strength and weakness of electrolytes, the length and width of the electrodes, and the frequency of the alternating current can affect the rate of electrolysis of water. Commonly speaking, the stronger the electrolyte is, the faster the rate of electrolysis will be. NaOH and HNO3 are strong electrolytes, but the amount of the gas is zero during electrolysis by using alternating current. Maybe both of electrolytes react with stainless-steel electrodes to form some kinds of protective layers to affect the conduction of current. When copper bars, carbon bars, and iron nails are used as electrodes, either the alternating current or direct current is used, the amount of the gas is very small. Maybe these electrodes react with oxygen produced during electrolysis to form oxidized layers to block the conduction of current. Long and wide electrodes produce more amount of the gas. The amount of the gas increases when the frequency of the alternating current increases. The longer the distance between electrodes is, the smaller the amount of the gas will be. The smaller the angle between electrodes is, the smaller the amount of the gas will be, too. When the number of multiple electrodes in parallel increases, the total amount of the gas almost increases. The amount of the gas is smaller at the farther electrode. The amount of the gas at the electrode at the same distance becomes smaller when the number of multiple electrodes in parallel increases. At the same voltage, the effective current of the alternating current is about 0.707 of that of direct current. So we can predict that the total amount of the gas elect rolyzed by alternating current must be about 0.707 of the total amount of the gas electrolyzed by direct current. When we used stainless-steel electrodes and the electrolyte- H2SO4, we found the ratio was about 0.4286. Maybe the system of the electrolysis of water doesn’t obey the ideal linear system of Ohm’s Law and some part of electrical energy is wasted by increasing the temperature of the water and the oxidization of electrodes. 交流電解普遍水溫較高且兩極都有被氧化現象,直流電解則只有正極有上述現象,可能是交流電有類似微波爐的原理,電流交替時造成水分子震盪發熱。電解質強弱、電極種類、電極長短粗細、交流電頻率會影響電解水速率:強電解質較快,但NaOH 、KNO3 雖是強電解質,在交流電解時,氣體產生量幾乎是零,這可能是他們與不銹鋼電極反應形成某種保護層而影響導電;以銅棒、碳棒、鐵釘為電極時,不管是交流電或直流電,氣體體積都很小,這可能是這些電極和產生的氧氣反應,形成氧化層阻礙了導電;長的和粗的電極氣體產生量較多;交流電頻率越大,則電解所產生的氣體量也隨之增加;電極之間的距離越大兩極的氣體體積越小;兩電極之間的角度越小,兩極的氣體體積越少;多重電極並聯的個數越多,總氣體體積約略越大,距離越遠的氣體體積越小,同距離的氣體體積隨並聯的個數越多氣體體積越小。在相同電壓下,交流電輸出的均方根電壓(電流)為直流電電壓(電流)的0.707 倍(1/√2),所以推測交、直電解水的氣體總體積比值也應為0.707,但我們以不銹鋼為電極、H2SO4 為電解液下比值為0.4286,這可能是本電解水系統並非為遵守歐姆定律的理想線性系統,且電解水時部分電能被消耗在水溫的升高及電極的氧化上。

燃料電池用之磺酸化SEBS-奈米粒子複合膜製備與性質研究

聚苯乙烯(S)-聚乙烯(E)-丁二烯-1(B)-聚苯乙烯(S) (polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene,簡稱SEBS)是目前直接甲醇燃料電池的質子交換膜研究中常用於與Nafion比較的膜材。Nafion的價格昂貴,且其高甲醇滲透率將造成電極毒化,故本研究探討不同製程與添加不同奈米粒子所製作之質子交換膜特性,以有效降低甲醇滲透。結果發現,添加之ZrP為層狀結構,增加甲醇通過親水區域端的難度,能有效阻擋甲醇滲透。且藉由磺酸根官能基團,以及本身帶有質子傳導性質,所以與Nafion的PTC數據差距不大,因此C/P值較Nafion高。未來可改變不同磺酸化程度,並在SSEBS內添加不同奈米粒子,並對於質子交換膜的持久性及實際應用之探討。

化學中的數學與程式設計

When we were learning about organic compounds at school ,there was a unit discussing the isomers of alkane .Our teacher made us practice drawing all the structural formula of the isomers from hexane to nonane .We were much interested in the subject .However ,we often missed or duplicated some isomers .Thus , we began to think if it is possible to find a way by developing programs to let the computer calculate the exact number of the isomers of alkane . After discussion ,we set up a complete coding system .We numbered the isomers in the way that computers could decode and then wrote them in C language. Through computer execution ,the numbers of the isomers from C1 to C20 all match those on the reference website. According to the same concept , we also find a way to calculate the number of alkane with one substituted group . In the future,our goal will be focused on the research of multi- substituted alkane and cyclokane. In addition , the ionic crystal accumulation model are so variable. Take the double face-centered accumulation of NaCl for example, when the ion pairs are extended to the infinity , the potential energy of attractive field will approach a constant which is named as the Madelung Constant. We also managed to write a computer program with C language to approach this convergence with three models, including cube , octahedron , and sphere . The result turned out to be that the data of the sphere was less stable . In the other two models , when “n” is up to 43 layers , the data is identical with that on the reference website to the eight decimal point . 在學校裡學習有機化合物有關烷類異構物這個單元,老師讓我們練習畫出己烷~壬烷的所有異構物結構式,這引起我們極大的興趣!但常一不小心就漏掉或多出幾個,我們開始思考:能不能找到一個方法並設計成程式,讓電腦執行以找出烷類異構物?經過討論,我們建立了一套完整的編碼系統,將各異構物以電腦可解讀的方式編號,並以C 語言寫成程式。透過電腦執行,各碳數化合物自C1至C20都與參考網站吻合。依相同觀念,我們也設計出烷類含一個取代基的異構物數目。將來努力的目標為:多取代基及環烷類之研究!另外,離子晶體堆積模型變化多端,以NaCl 雙面心堆積為例,其引力場位能,當離子對延伸至無限大時,這個值將趨近於一個常數,又稱為馬德隆常數。我們嘗試以C 語言設計電腦程式,用三種模型(正立方體、正八面體、圓球)來逼近並求得這個收斂值。執行結果是:圓球數據較不穩定;而另二種模型到n=43 層以上,其數值大小與參考網路上的數值,在小數點以下8 位完全相同。