Sunday, 28 November 2010

Self-Reliant Learning Process

This semester, after 14 weeks of lecture and tutorial sessions as well as an open book test, more that a hundred students taking Principles of Chemistry should have been ready for the next real test that is final examination. As a lecturer (teacher precisely), I would like to see all of my students come out from the examination hall with a happy face and a big smile just because they sincerely studied and answered the questions with confident. 

Tuesday, 23 March 2010

SCES2324 Petrochemistry Exercise


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SCES2324 Petrochemistry Exercise 1

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Note: The discussion on Exercise 1 will be held on 3 March 2011 (12 - 1 pm). Please get your answers ready. Time table for Exercise 2 will inform later.

Real Gases


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This topic is discussing on more realistic situation where we can observe the experimental data was deviated from perfect gas law. There were situations or parameters that can be manipulated in order to "revise" the prefect gas equation and fit with the experimental observation. In this topic, CO2 has been chosen as an example to explain the intermolecular interaction, compression factor, virial coefficient, condensation and critical constant. These are resulting from the situation where we have a trapped gas in a container with variable molar volume and pressure at determined temperatures. 

In more advanced approach, Van der Waals was rather improved the perfect gas equation by applying smaller volume. Hence, affect the frequency and force of collision of the gas molecules. The redefine equation also bring about the prediction of critical compression factor of a gas. 

Thursday, 18 March 2010

The Properties of Gases


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This topic is a discussion on the perfect gas equation, starting from introducing pressure and temperature characters based on gas molecular aspect. It is also a revision on well known laws: Boyle, Charles and Avogadro. These principles lead us towards the kinetics model of gases. From both kinetic model and perfect gas equations, we able to derive an equation to estimate the velocity of a gas. The equation even more refined by applying Maxwell distribution where the two factors; mass of gas molecules and temperature of a gas were considered. These factors are similarly important as the frequency of gas molecules hitting each other and the wall. From these factors, we are also able to derive equation of the root means square speed, relative speed, mean speed and most probably speed. 

Reactions of Toluene and Xylene


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Kali ini kita masih membincangkan topik aromatik dan tindakbalas berkaitan dan juga aplikasi sebatian dan terbitannya. Topik utama dan yang penting adalah tindakbalas daripada toluena dan xylena. Seperti benzena, kedua-dua sebatian toluene dan xylena boleh ditransformasikan kepada sebatian-sebatian lain yang lebih berguna dan tinggi nilainya dipasaran. 
Selamat mentelaah!

Saturday, 27 February 2010

Introduction to Modern Quantum Chemistry

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**SCES/P1200-Modern Quantum Chemistry - Part 2


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Versi Melayu
Topik ini merupakan pengenalan dan pendedahan awal tentang kuantum kimia moden. Sebagai kesinambungan kepada topik terdahulu, iaitu sifat-sifat atom dan struktur elektronik atom daripada prespektif teori klasik fizik dan tenaga terkuanta, topik ini menjelaskan bagaimana menghubungkan sifat-sifat atom dan lokasi elektron dalam bentuk terkuanta atau dalam nilai diskrit. 

Anda boleh mengandaikan sifat elektron (sifat dualiti gelombang-partikel dan  ketakpastian Heisenberg) sebagai asas memahami lokasi suatu elektron. Tahukah anda bahawa Erwin Schrodinger begitu bijak menghuraikan elektron sebagai bersifat standing wave dalam bentuk matematik yang disebut sebagai fungsi gelombang. (Salah satu contoh standing wave adalah getaran dalam tali gitar!) Persamaan ini dikembangkan daripada satu dimensi kepada tiga dimensi (dx, dy, dan dz). 

Menggunakan persamaan yang sama, Born mentafsirkan jika fungsi gelombang ini dikuasaduakan, ia menjadi kepadatan kebarangkalian menemui elektron. Persamaan yang menarik ini membayangkan pengorbitan elektron pada atom mudah seperti hidrogen dan helium.

Seterusnya, persamaan Schrodinger ini digunakan di dalam persamaan tenaga terkuanta di mana komponen tenaga kinetik mengandungi elemen fungsi gelombang manakala tenaga keupayaan mempunyai elemen jarak elektron daripada nuklei. Persamaan ini malangnya hanya berkesan untuk perubahan lokasi yang sangat kecil sahaja.

Oleh kerana lokasi elektron berkebarangkalian berada dalam suatu bentuk sfera, maka persamaan Schrodinger yang berasaskan koordinat Cartesian ini diolah semula dengan koordinat sfera berkutub oleh Eugene Wigner. Maka fungsi gelombang ini mempunyai dua bahagian iaitu: fungsi gelombang bersudut dan fungsi gelombang berjejari.

Akhirnya, persamaan ini berkembang mengikut peringkat pengorbitan lebih kompleks dan dianggap berjaya menerangkan kebarangkalian penemuan elektron dalam suatu pengorbitan, bukannya terletak dalam orbit-orbit seperti yang disarankan oleh Borh suatu ketika dulu.

English Version
It is an introduction to modern quantum chemistry. As a continuity from previous topic, that is atomic characters and electronic structure from both classical theorem dan quantization of energy, this topic may describes how to relate atomic properties and location of electron in quantized manner. 


You may assume that electron properties (wave-particle duality, Heisenberg uncertainty etc.) to be important in understanding the location of an electron. Erwin Schrodinger was successfully derived a mathematical equation to describe electron as a standing wave. (One example of standing wave is wave in guitar string!) The equation was expanded from one dimension into three dimensional equation (dx, dy and dz).

By using the similar equation, Born was interpreted that if the wave function is squared, the product will be the probability density of finding the electron. This interesting equation manifests the orbital of electron in simple atom such as hydrogen and helium. 

Consequently, the Schrodinger equation was used in the equation related to the quantization  of energy where kinetic energy component consists of wave function element and potential energy has element of electron-nuclei distance. However, the equation only valid for very small change of delocalization.

Because of the probability of finding the electron in spherical, the Schrodinger equation that was based on Cartesian coordination, had been re-derived using spherical polar coordination by Eugen Wigner. Therefore, the wave function now has two division: angular wave function and radial wave function.

Finally, the equation was expanded for more complex and higher order of orbitals and most successful equation to describe the probability to find electron in an orbital, not located in  orbits as previously suggested Borh.








Tuesday, 9 February 2010

Covalent Catalysis (Pemangkinan Kovalen)


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Covalent catalysis is another form of catalysis that is important in many enzymatic catalysis. In the beginning of the topic, hydrolysis of p-nitrophenyl acetate by chymotrypsin has been discussed. There are three possible reasons to the rapid initial reaction rate: (a) product inhibition, (b) conformation change and (c) product releasing and intermediate formation. 

The similar reaction has been performed in the presence of o-(N,N-dimethylaminomethyl) benzyl alcohol to mimic chymotrypsin. From the results, it is quite clear that covalent bonding was formed by nucleophilic attack to electron sink of carbonyl group. Perhaps, the nucleophilic attack was enhanced by the adjacent amino group that "deprotonating" the hydroxyl group. The intermediate is the key point to deduce the formation of covalent bonding between the catalyst and the substrate as well as producing the main product (p-nitrophenol).

There are a couple of examples of such activity: decarboxylation of acetoacetate and stereoselective nucleophilic attack to an alkene.

Hopefully, the discussion will help to understand the nucleophilic catalysis.

Tindakbalas Sebatian Aromatik - Benzena




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Topik terdahulu telah dibincangkan sifat fizikal sebatian aromatik, pengeluaran bahan aromatik menerusi proses penulenan (proses fizikal) dan juga peningkatan hasil melalui transformasi struktur molekul (proses kimia).

Dalam topik seterusnya ini, tindakbalas sebatian aromatik dalam skala industri akan dibincangkan secara lebih terperinci termasuk pengubahan sebatian aromatik khususnya benzena kepada struktur molekul yang dikehendaki seperti styrene, phenol, aniline dan anhydride

Styrene dihasilkan bermula daripada tindakbalas antara benzena dengan etilene bagi menghasilkan etilbenzena. Proses seterusnya adalah dehidrogenasi secara langsung yang menghasilkan styrene. Terdapat dua  jenis proses dehidrogenasi dibincangkan dengan lebih terperinci iaitu adiabatik dan reaktor tubular. 

Pengeluaran phenol tidak kurang pentingnya di mana kaedah Raschig dan kaedah Cumene dibincangkan. Perbandingan diantara kedua-dua kaedah yang popular ini dibuat berdasarkan pelaburan, bahan mentah, peratusan hasil dan juga hasil sampingan.

Tindakbalas benzena dalam keadaan tertentu untuk penghasilan nitrobenzene, aniline, anhydride dan sulphonate benzene juga dibincangkan. Ia penting untuk diketahui kerana bahan-bahan tersebut banyak sekali digunakan dalam industri pembuatan, perubatan dan surfaktan.

Monday, 11 January 2010

Pengenalan kepada Aromatik daripada Petroleum



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Setelah membincangkan pengeluaran dan tindakbalas berkaitan naftena (sikloalkana), dalam topik lepas, kini kita berpeluang membincangkan tentang pengeluaran sebatian aromatik daripada petroleum pula. Topik ini sangat penting kerana sebatian aromatik bukan sahaja mempunyai nilai pemintaan yang tinggi malah hasil atau produk berasaskan aromatik juga pelbagai. Dalam revolusi industri khususnya, sebatian aromatik sangat diperlukan dalam pelbagai lapangan seperti penyediaan bahan polimer, pelarut, bahan pemula, dan lain-lain lagi.


Topik ini menjurus kepada pengenalan awal sebatian aromatik daripada petroleum. Sifat dan kaedah pengeluaran bahan juga dibincangkan sebagai satu pengenalan kepada sebatian ini. (nota*)


Diharapkan ini dapat memberikan masukan awal sebelum proses tindakbalas selanjutnya dibincangkan kemudian.

Approximation

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Catalytic activities can be observed naturally in many type of protein enzymes. The reactions have been speed up significantly compared to similar reactions without the catalyst. It is quite reasonable to say that bringing the substrates to the binding site will help the reaction to behave slightly different. The questions are, what cause the binding activity and how molecules or reagents participate in the "modified" the possible path of reactions? 


(will continue soon...)

Struktur Electronik Atom (Electronic Structure of Atoms)

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#SCES/P1200-Tutorial 1

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Versi Melayu


Topik yang dibincangkan ini merupakan suatu lanjutan kepada atom dan komponen-komponen atom. Siri ini agak kritikal kerana ia merupakan peralihan kepada pemahaman konsep atom daripada perspektif fizik klasik kepada mekanik quantum.

Diselitkan diawal perbincangan adalah beberapa isu yang menjadikan fizik klasik tidak releven dalam menerangkan fenomena tersebut umpamanya fenomena jasad legap (blackbody) dan fotoelektrik (photoelectric). Bermula daripada saranan Max Planck tentang hubungan tenaga dan panjang gelombang sebagai suatu yang ter"kuanta", maka wujud prespektif baru dalam menerangkan konsep atom dan struktur elektronik atom itu sendiri menggunakan mekanik quantum (nota*).

Antara saranan-saranan yang dianggap penting adalah oleh Einstein, Bohr dan Heisenberg, dalam menerangkan sifat dan struktur binaan atom yang bukan sahaja kemudiannya dapat menerangkan atom mudah seperti H dan He, malah atom-atom berjisim besar dan molekul (nota**, nota***).

Diharapkan perbincangan ini dapat memberikan gambaran lebih jelas tentang struktur binaan atom dan struktur elektroniknya.


English Version


The discussed topic is an extra information on atoms and their components. It is a quite critical topic because the issue shifted from classical physics to quantum mechanics.

In the beginning, a few problems have been highlighted but not easy to be explained from classical physics such as blackbody and photoelectrics phenomena. From the early suggestions on the energy quantization related to the wavelenghts by Max Planck, a new perspective in order to explain the atomic concept and their electronic structure has emerged using quantum mechanic (note*).

Some of the important hypothesis made by Einstein, Bohr and Heisenberg, not just to explain the behaviour and how a simple atom like H or He is constructed, but also relevent for bigger atom and molecules (note**, note***).

Perhaps, from the discussion, we able to get a clear picture of atomic structure and most importantly their electronic structure.

Tuesday, 5 January 2010

Struktur Atom (The Structure of Atom)


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Versi Melayu

Prinsip-prinsip kimia telah dibentuk untuk peringkat awal kursus kimia dan sebagai persediaan untuk mendapatkan maklumat lanjut dalam subjek berkaitannya. (nota*)

Di awal kursus, beberapa topik tertentu berkenaan bahan, termasuk hukum-hukum berkaitan, klasifikasi bahan, dan komponen suatu atom, telah dibincangkan secara umum. Konsep atom dibawa secara berperingkat bermula dari aspek sejarah, seterusnya penemuan sifat atom mengikut pandangan fizik klasik. (nota#, nota@)


Diharapkan perbincangan ini dapat mengukuhkan lagi konsep atom dan molekul berdasarkan fizik klasik sebelum teori-teori tersebut dimansuhkan oleh teorem kuantum mekanik.


English Version


Principles of chemistry was designed for entry level of chemistry course and as a preparation for acquiring further information in chemistry-related subjects. (note*)

In the beginning, certain topics on matter, including some related laws, classification of matter, and components of an atom, was briefly discussed. The concept of atom was discussed gradually from the aspect of history, until the finding of atomic properties from the point of view of classical physics. (note#, note@)

Perhaps from the discussion, we able to get a clear idea on atomic and molecular concept based on classical physics theories before the theories were disqualified by quantum mechanic theorem.

Monday, 4 January 2010

Pengeluaran Naftena

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Naftena adalah hasil petrokimia dalam bentuk hidrokarbon tepu dan berbentuk siklik (gelang) - cyclohydrocarbon. Ia merupakan salah satu bahagian yang besar dalam produk petroleum.

Topik in berkisar tentang pengeluaran naftena dan hasil-hasil daripada tindakbalas naftena. Pada peringkat awal, diterangkan bagaimana naftena ini dikeluarkan secara fizikal. Kemudian, peratusan hasil naftena dapat ditingkatkan secara kimia melalui proses tertentu hidrogenasi dan penutupan hidrokarbon alifatik. Sifat-sifat fizikal tidak kurang pentingnya kerana terdapat faktor bilangan atom karbon dan bentuk molekul. (nota 1*)

Bahagian seterusnya adalah tindakbalas-tindakbalas bahan naftena kepada bentuk-bentuk molekul lain. Proses ini penting untuk menjana lebih banyak julat atau barisan produk daripada naftena itu sendiri. Antara tindakbalas yang dibincanagkan adalah pirolisis, oksidasi, penitratan, pengklorinan dan penyediaan kaprolaktam. (nota 2#)

Diharapkan perbincangan ini dapat memberikan maklumat awal, pada dasarnya pengeluaran naftena dan hasil-hasilnya daripada tindakbalas biasa kimia organik, tetapi lebih kepada skala industri.