• Title/Summary/Keyword: Ionic compound

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On Electric Field Induced Processes in Ionic Compounds

  • Schmalzried, H.
    • Journal of the Korean Ceramic Society
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    • v.38 no.6
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    • pp.499-505
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    • 2001
  • The behaviour of ionic compound crystals under combined chemical and externally applied electrical potential gradients is discussed. Firstly, a systematic overview is given. Then a formal analysis follows. The transport equations of the ions and the electric defects predict that even with reversible electrodes demixing, and in particular decomposition of the compound will occur if the applied d.c. current density is sufficiently high. These predictions are illustrated by appropriate experiments. With the help of the solid solution (Me, Fe)O, where Fe-ions are the dilute species, we investigate experimentally the behaviour of a ternary ionic crystal under a d.c. electric current load. All the compounds were placed in a galvanic cell, and the internal reactions which then could be observed were driven by the electric field in this cell. In addition, we discuss the influence of the electric field on the classical solid state reaction AX+BX=ABX$_2$, if again the reaction couple is placed in a galvanic cell.

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Analysis of the Level of Cognitive Demands about Concepts of Ionic Compounds and Molecule on Science 2 Textbooks in Junior High School (II) (중학교 과학2 교과서에 서술된 이온 결합 화합물과 분자 내용이 요구하는 인지 수준 분석(제II보))

  • Kang, Soonhee;Bang, Dami;Kim, Sun-Jung
    • Journal of the Korean Chemical Society
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    • v.56 no.6
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    • pp.739-750
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    • 2012
  • The purpose of this study is to analyze the cognitive demands level of the description about 'pure substance and mixture compound', 'ionic compound', 'molecule' on the 'science2' textbooks by the 2007 revised curriculum. The three types of Curriculum Analysis Taxonomy have been used to analyze the cognitive demands level of those contents on the 6 kinds of 'science2' textbooks. The first, the cognitive demand level about 'pure substance and mixture compound' on many textbooks is a late concrete operational stage because of class inclusion and hierarchical classification. And the descriptions as 'pure substance is conserved even when mixed with other pure substance' is a early formal operational stage. The second, the cognitive demand level about 'ionic compound' and 'molecule' is a early formal operational stage, because of "Formal modeling is the indirect interpretation of reality by deductive comparison from a postulated system with its own rules" and "Atoms have a structure". The third, the terms as 'ionic bonding', 'ionic compound', 'chemical formula', 'covalent bonding', 'covalent compound', and 'molecular formula' have been used on many 'science2' textbooks. Those terms would be used later on 'chemistry I' and 'chemistry II' in senior high school but not even 'science3' and 'science'.

An Analysis of Concept Description and Model and Student Understanding About Ionic Compound in Textbooks Developed Under the 2009 Revised National Curriculum (2009 개정 교육과정에 따른 교과서에서 이온 화합물의 설명 개념과 모형 및 학생 이해도 분석)

  • Shin, He Young;Woo, Ae Ja
    • Journal of the Korean Chemical Society
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    • v.60 no.5
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    • pp.362-373
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    • 2016
  • In this study, ionic compound in the science textbooks developed under the 2009 revised national curriculum were analyzed in terms of the scientific concept and model description and the student understanding through the questionnaires. Analysis of textbooks was performed for science2 of middle school and chemistry I & II of high school. Questionnaire was carried out with 194 students including middle school 2nd grade and high school 1st-3rd grade. The results are as follows: First, as a result of analysis of textbooks, scientific concepts and models used to explain the ionic compound showed differences depending on the types of textbooks. In addition, scientific models were provided with or without explanation for the scientific concepts. Second, analysis of the questionnaire showed that students didn’t properly understood scientific concepts and models in the ion formation, stoichiometric ratio between ions.

A Survey of Secondary School Science Teachers’ Thinking on Classifying Phenomena Related to Dissolution of Ionic Compound and Acid into Physical and Chemical Change (이온결합 화합물과 산의 용해 현상을 물리변화와 화학변화로 구분하는 문제에 대한 중·고등학교 과학교사들의 인식 조사)

  • Baek, Seong Hye;Kim, Seon Gyeong
    • Journal of the Korean Chemical Society
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    • v.46 no.6
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    • pp.561-568
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    • 2002
  • This study examined secondary school science teachers' thinking on physical and chemical change. For this research, we analysed the answers of 80 secondary school science teachers. According to the result of the analysis,teachers had various opinions when they classified phenomena of dissolving ionic compound or diluting acid into phys-ical change and chemical change. Many teachers tended to classify similar phenomena into different change when those were represented with different focus. It means that teachers' opinions were not consistent.

Influence of feed water chemistry on the removal of ionisable and neutral trace organics by a loose nanofiltration membrane

  • Nghiem, Long D.
    • Membrane and Water Treatment
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    • v.1 no.2
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    • pp.93-101
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    • 2010
  • This study examined the effects of feed water chemistry and membrane fouling on the rejection of trace organics by a loose nanofiltration membrane. One ionisable and one non-ionisable trace organics were selected for investigation. Results reported here indicate that the solution pH and ionic strength can markedly influence the removal of the ionisable trace organic compound sulfamethoxazole. These observations were explained by electrostatic interactions between the solutes and the membrane surface and by the speciation of the ionisable compound. On the other hand, no appreciable effects of solution pH and ionic strength on the rejection of the neutral compound carbamazepine were observed in this study. In addition, membrane fouling has also been shown to exert some considerable impact on the rejection of trace organics. However, the underlying mechanisms remain somewhat unclear and are subject to on-going investigation.

Pd(II) Catalyzed Copolymerization of Styrene and CO in Quaternary Ammonium Ionic Liquids

  • Tian, Jing;Guo, Jin-Tang;Zhu, Cheng-Cai;Zhang, Xin;Xu, Yong-Shen
    • Macromolecular Research
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    • v.17 no.3
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    • pp.144-148
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    • 2009
  • Poly(1-oxo-2-phenyltrimethylene) was synthesized by palladium-catalyzed copolymerization of styrene and carbon monoxide in quaternary ammonium ionic liquids. The $[Pd(bipy)_2][PF_6]_2$ compound had relatively more catalytic activity than $[Pd(bipy)_2][BF_4]_2$ in ionic liquids. The catalytic activity of palladium (II) composite catalyst was superior to the catalyst formed in situ from palladium acetate, 2,2-bipyridyl, and $X^-$ ($X^-=PF_6^-$, $BF_4^-$) in ionic liquids. The effects of the volume of ionic liquids, reaction time and benzoquinone content on the copolymerization were also described.

XPS Investigation of A3 Coupling Reaction in Room Temperature Ionic Liquids

  • Kwon, Ji-Hye;Youn, So-Won;Kang, Yong-Cheol
    • Bulletin of the Korean Chemical Society
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    • v.27 no.11
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    • pp.1851-1853
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    • 2006
  • We herein report a new analytical application of XPS to the identification of organic molecules in room temperature ionic liquid for the first time. An organic compound, propargylamine (1), produced in 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][$PF_6$]), which is one of the room temperature ionic liquids (RTILs), via $A^3$ coupling reaction, is characterized by means of x-ray photoelectron spectroscopy (XPS) rather than using conventional organic compound analysis techniques. There are four non-equivalent carbons in RTILs and 1 each. The ratios of normalized integrated areas of the deconvoluted binding energy of core electron of carbon (C1s) peaks are well matched to the number of carbons in those compounds. The binding energies of C1s of the featured carbons in 1, C4 (sp carbons in acetylene group) and C5 ($sp^2$ carbons in benzene ring), are assigned 286.2 and 285.4 eV, respectively. These results will be able to provide an important tool and a new strategy for the analysis of organic molecules

Phase Equilibria of Ionic Liquid/Organic Compound/Supercritical CO2 Systems (이온성액체/유기화합물/초임계이산화탄소계의 상평형)

  • Lim, Bang-Hyun;Kim, Jong-Won;Paek, Sang-Min;Son, Bo-Kook;Lee, Yong-Rok;Lee, Chul Soo;Lee, Huen;Ra, Chun-Sup;Shim, Jae-Jin
    • Clean Technology
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    • v.12 no.3
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    • pp.128-137
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    • 2006
  • The volume change of an ionic liquid and the phase separation behavior of room temperature ionic liquid(RTIL)/organic compound mixture in supercritical carbon dioxide were measured in a high pressure view cell. 1-Butyl-3-methylimidazolium hexafluorophosphate ([bmim][$PF_6$]) and 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][$BF_4$]) was used as ionic liquid(IL). and methanol and dimethyl carbonate were used as organic compound. For a fixed amount of [bmim][$PF_6$] the lower critical endpoint (LCEP) pressure, where the liquid phase is split, decreased as increasing the amount of organic compound. The LCEP pressure became higher as the water content of ionic liquid was higher. However, for water contents above a certain value, no LCEP was formed. LCEP appeared 1.0 MPa higher for a mixture with [bmim][$BF_4$] than with [bmim][$PF_6$]. There was almost no difference in the K-point pressures for different types of ionic liquid and for different amounts of organic liquid. When the concentration of ionic liquid([bmim][$PF_6$]) (IL/(IL+MeOH)) in the initial liquid mixture was larger than 5.9 mol% at the LCEP of the mixture, the volume of $L_1$ because larger than the volume of $L_2$. When it was smaller, however, the volume became smaller, too. The volume change of ionic liquid in the presence of carbon dioxide decreased as increasing the temperature, while it increased as increasing the pressure. For temperatures between 313.15 to 343.15K at 300 bar, it was about 123~125 % of the original volume.

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Estimated Bioaccumulation properties of Acetanilide using BCFWIN (BCF WIN을 이용한 Acetanilide의 생물농축특성 평가)

  • Kwon, Min-Jeong;Choi, Yoon-Ho;Song, Sang-Hwan;Park, Hye-Youn;Koo, Hyun-Ju;Park, Kwang-Sik
    • Environmental Analysis Health and Toxicology
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    • v.16 no.4
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    • pp.223-226
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    • 2001
  • Acetanilide is a High Production Volume Chemical, which is produced about 2,300 tons/year in Korea as of 1998 survey. Most is used as an intermediate for synthesis of pharmaceuticals and dyes. The chemical is one of seven chemicals, which are under the frame of OECD SIDS program sponsored by National Institute of Environmental Research of Korea. Regarding the information on the environmental fate. bioconcentration is one of important factor to estimate the environmental tranfer. However, measurement of bioconcentration needs high expense and time. For this reason, OECD recommends to use BCFWIN model to estimate bioconcentration of organic chemicals, BCFWIN estimates the bioconcentration factor (BCF) of an organic compound using the log octanol-water partition coefficient (Kow) of the compound. Structures are entered into BCFWIN through SMITES (Simplified Molecular Input Line Entry System) notations. The BCFWIN method classifies a compound as either ionic or non-ionic. ionic compounds include carboxylic acids, sulfonic acids and salts of sulfonic acids, and charged nitrogen compounds (nitrogen with a + 5 valence such as quaternary ammonium compounds). All other compounds are classified as non-ionic. In this study, bioaccumulation of acetanilide was estimated using BCFWIN model based on SMIIES notation, chemical name data and partition coefficient as one of environmental fate/distribution of the chemical elements.

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The Soft Material Obtained from an Europium (III)-Containing Ionic Liquid

  • Shao, Huifang;Wang, Yige;Li, Dan
    • Bulletin of the Korean Chemical Society
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    • v.32 no.3
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    • pp.973-976
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    • 2011
  • The addition of organic ligand (${\beta}$-diketone or heterocyclic compound) to the europium (III)-containing ionic liquid resulted in bright luminescent soft materials with the molar ratio of europium/ionic liquid (IL)/ligand being 1:3:1 that exhibit bright red light under UV lamp. The luminescent properties such as emission features and lifetime of $^5D_0$ $Eu^{3+}$ excited level are dependent on the organic ligands. The materials were characterized by FT-IR and luminescence spectroscopy. The data shows that at least parts of the ILs (carboxylic acid) are replaced with ${\beta}$-diketone ligand rather than the formation of europium complex with the molar ratio of $Eu^{3+}$:IL: ligand being 1:3:1, while no ILs could be replaced by the heterocyclic ligand such as Bpy and Phen.