Wednesday, June 30, 2010

Chemical, Toxicity and Risk

Life is not risk-free. We all take many risks everyday, often without even thinking about it. We may decide to ride a motorbike rather than a "microlet", even though possibility to get accident on a motorbike is greater than that on a microlet. Some people decide to smoke cigarettes, even though they know that smoking has killed many people. Many people like eating "cilok" even though they might know that cilok contains sauce colored with red coloring agent usually used to color textile, and potentially dangereous monosodium glutamate (MSG) as flavor enhancer. Many reports indicate that our food often contains pesticides and dangerous additive. Newspapers often report that our lands is polluted by toxic waste dumps and some medicines are unsafe. How bad are the risks from chemicals, and how are the risks evaluated ?

it is important to realize that everything, including our body, is made of chemicals. There is no chemical free food, cosmetic, cleanser, or anything else. In addition, there is no meaningful difference between "natural" substance and "synthetic" one. A chemical is a chemical, whether it is natural or synthetic. Many naturally occurding substances such as strychnine and morphine are very toxic, and many synthetic substances such as polyethylene and glass are harmless.

Risk evaluation of chemicals is carried out by exposing test animals, usually mice, to a chemical and then monitored for signs of harm. To reduce the time and the expense required for testing. the amount of chemicals administered is hundred or thousand of times larger than those people might normally encounter. The acute chemical toxicity observed in animal tests is reported as an LD50 value, the amount of a chemical per kilogram of body weight that is a lethal dose for 50% of the animal tests.

The risk of human exposure to a given chemical is still not easy to assess even though the LD50 value of it has been obtained in test animals. All chemicals are toxic to some organisms to some extent, and the difference between medicine and toxin is often a matter of quantity. Vitamin A, for example, is necessary for vision, yet it might cause cancer at high doses. Arsenic trioxide is very poisonous. However, recent research has shown that it to be effective at inducing remissions is some types of leukemia.
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Friday, June 25, 2010

Award Pertama Dari Sahabat

Kerja keras akhirnya menunai hasilnya juga, dengan mendapatkan award dari seorang sahabat lepembusu13, kata-kata para blogger sih, kalau blog ngga ada award, bagaikan sayur tanpa garam. Atas penghargaan award yang telah diberikan saya ucapkan terimah kasih, rasa senang nie ta bagikan dengan kawan-kawan para blog, maka saya akan membagikan lagi penghargaan blog award kepada 10 orang berikut ini:

1. muzzymusthofa
2. tugala
3. gudangrusak
4. ichsandi
5. downloadgratis34
6. sweetcrazystudent
7. denchiel78
8. sasaciq
9. ilmupengetahuanterbaru
10. alkatro

Aturan Main:
Bagi siapa saja yang mendapatkan penghargaan blog award ini (antara lain yg tersebut di atas) diharuskan untuk kembali membagikan penghargaan blog award yg telah diterima kepada 10 blogger anggota atau teman masing-masing. Selanjutnya si penerima penghargaan blog award harus meletakkan link-link berikut ini di dalam blog atau artikel masing-masing.

1. Dholpin's Blog
2. Kumpulan PTC
3. Loudy Blog
4. All Information For Us
5. Sumber Informasi
6. Coret-coretan di Blog
7. Teka-teki Informatika
8. Ahmil's Blog
9. lepembusu13
10. faijal chemistry

Sebelum meletakkan link-link di atas, hapus terlebih dahulu peserta nomor 1 dari daftar. Sehingga semua peserta naik 1 level. Peserta nomor 2 menjadi nomor 1, nomor 3 jadi 2, dst. Kemudian masukkan link Anda sendiri di bagian paling bawah (nomor 10). Tapi ingat...!!!, kalian semua harus adil dalam menjalankannya. Jika tiap penerima award mampu memberikan award ini kepada 5 orang saja dan mereka semua mengerjakannya , maka jumlah backlink yang akan didapat adalah:

Ketika posisi kamu 10, jumlah backlink = 1
Posisi 9, jumlah backlink = 5
Posisi 8, jumlah backlink = 25
Posisi 7, jumlah backlink = 125
Posisi 6, jumlah backlink = 625
Posisi 5, jumlah backlink = 3,125
Posisi 4, jumlah backlink = 15,625
Posisi 3, jumlah backlink = 78,125
Posisi 2, jumlah backlink = 390,625
Posisi 1, jumlah backlink = 1,953,125

Dan semuanya menggunakan kata kunci yang sObat inginkan. Dari sisi SEO (Search Engine Optimation) sobat sudah mendapatkan 1,953,125 backlink dan keuntungannya, blog sobat akan mendapatkan traffic tambahan, apalagi jika ada yang meng-klik link ke blog sobat. Jadi, jangan sia-siakan award ini ya sobat!
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Tuesday, June 22, 2010


Lung cancer kills many people in the world. The leading cause of lung cancer is tobacco smoke. The second leading cause is radon, a naturally occuring radioactive gas. Radon is relatively harmless gas. The danger arises when radon decays to produce polonium. if this happen in your lung, you risk of lung cancer increases. The combination of radon and tobacco smoking is more deadly than radon gas alone. it is up to 15 times more deadly. Radon is transformed ito polonium by a nuclear reaction. The polonium particles formed attach themselves to surfaces such as well cloth and furniture. When there is tobacco smoke in the air, much of polonium is attracted to the particles of smoke. Cigarette smoke may remain in the air inside a building for a long time. A single cigarette burned in a room increases the concentration of polonium in the air by 25%, after about five hours. This concentration remains constant for about nine hours before trailling off. Burning 20 cigarettes for a 24-hour period increases the concentration of polonium in the air up to 300%. Breathing this air result in risk of radon induced lung cancer 15 times greater than breathing smoke free air with the same concentration of radon. The combination of radon with tobacco smoke affects everyone who spends time in such a building. This is one of the reasons for the prohibitions of smoking in public buildings and in public transports in developed countries.
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Friday, June 18, 2010


ChemDraw pro versi 8.0 merupakan salah satu program aplikasi dari Chem Office, untuk menggambar struktur 2D dalam bidang ilmu kimia, terutama kimia organik, biokimia, dan polimer. Software ini dapat membantu anda dalam menggambar struktur kimia dengan berbagai fasilitasnya, hanya dengan mengkliknya, tool tersebut akan bekerja untuk anda.

Tool-tool dalam ChemDraw mewakili berbagai macam bentuk ikatan yang dapat anda susun menjadi struktur kimia sehingga tidaklah sulit bagi anda untuk menggambarkan struktur yang kompleks sekalipun, bahkan juga dalam berbagai bentuk konformasi dan dalam bentuk proyeksi.

Struktur-struktur tertentu yang telah umum dapat digambar secara langsung dengan mengklik tool, seperti struktur cincin benzena, siklopentana, sikloheksana dan senyawa siklis yang lain. Tool dalam ChemDraw juga menyajikan gambar struktur untuk asam amino, DNA, dan RNA yang terdapat dalam template, anda tinggal klik, membawanya ke layar, drag, maka jadilah gambar struktur anda.

ChemDraw merupakan program aplikasi untuk menggambar yang di lengkapi dengan tool-tool sehingga pengguna dapat dengan mudah membuat gambar yang diinginkannya hanya dengan mengklik tool-tool tersebut, dengan ChemDraw anda tidak akan mengalami kesulitan di dalam membuat struktur kimia. Hal ini tentu sangat membantu anda dalam menulis skripsi, thesis, karya ilmiah, ataupun jurnal, bahkan anda juga dapat mengkomunikasikan struktur yang anda miliki ke dunia web jika komputer anda di lengkapi dengan program aplikasi ChemOffice yang lain. Gambar yang telah anda buat juga dapat dengan mudah dicetak atau dibawah ke dalam program aplikasi lain seperti Ms. Word.

ChemDraw juga dapat menganalisis struktur kimia yang telah kita gambar dengan menggunakan Analys Struktur pada menu Structure, di sini anda dapat mengetahui sifat-sifat fisik struktur tersebut, misalnya, titik didih, titik leleh, berat molekul, temperatur, tekanan, dll.
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Thursday, June 17, 2010

Molecular Models

Molecular models are often used to help explain the shape of molecules. In using the model we should remember that a model cannot represent fully the thing modeled, and it may ever mislead us if we imagine that the thing modeled must behave as predicted with model. Therefore we should know advantages and disadvantages of each model. There are many molecular models available. There of them are ball and stick, space filling and Dreiding models.

Ball and Stick or Tinkertoy Model

In this model atoms are represented as balls with certain colours. For examples: carbon is black, hydrogen is grey, nitrogen is blue, oxygen is red, and sulfur is yellow. The bond between two atoms is representend as a stick. Single bond is represented as a single stick. There are three advantages of this model. First, this model provides good three dimensional representational of molecules. Second, the number of bonds to each atom is correctly shown. Third, the bond lengths and bond angles are also correctly shown if the model is carefully made. The main disadvantage of this model is indicated with no overlap of electron clouds of the atoms forming the covalent bond. This may give an unfortunate idea of the "openness" of a molecule.

Space Filling Model

The basic units of this model are wooden spheres with certain colours from which parts have been cut of. When they are fitted together, they roughly represent covalent redii of the atom. The scale of the actual model is 1.00 cm = 1.00 Amstrong. The assembled model provides good three-dimensional representational of molecules and shows rather well bond angles and the relative sizes of the atoms forming covalent bonding compare to the ball and stick model. However, the number and the types of bonds to each atom is not shown.

Dreiding Model

This model is constructed of metal rod and tube joined together at a point that represent an atomic nuclei. The scale of this model is 1.00 cm = 0.40 Amstrong. This model provides good three-dimensional representation of molecules and shows quite precise relative size of bond lengths and bond angles in the molecules. There are two disadvantages of Dreiding Model. First, this model does not shown the three dimensional nature of atoms. Second, multiple bond is not represented. However, Dreiding model is often the favorite of research chemists because they represent so precisely the geometric relationship in molecules. So which type of model best represents the "true" structure of molecules? No model can exhibit all the characteristic of molecules. The remarkable fact is that molecular models have been so successfully used by chemists as they think about unseen and unseeable tiny molecules that make up all matter.
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Mendaur Ulang Plastik

Plastik pada dasarnya mempunyai waktu terurai yang tidak terbatas, tidak ada di alam ini yang dapat memusnakannya. Jika kamu mengubur piring plastik, mangkuk styrofoam dan kemudian menggalinya sepuluh tahun kemudian, tetap tidak akan ada perubahannya, bahkan menggalinya seratus tahun kemudian dan hasilnya akan tetap sama. Sampah yang mengandung plastik akan tetap ada bersama kita dalam waktu yang lama.

Beberapa plastik dapat dibakar sebagai bahan bakar karena mempunyai kandungan panas tinggi, namun plastik sering menghasilkan gas beracun atau korosif. Masarakat dapat mengurangi ketergantungannya terhadap plastik sampai pada tingkat tertentu. Penggunaan kotak hamburger dari kardus dan bahan pengepakan barang kiriman dari selulosa bukan dari styrofoam membantu, tetapi jawaban terbaik sampai saat ini adalah proses daur ulang.

Polimer termoplastik dapat dilelehkan dan dibentuk ulang, tetapi untuk melakukan ini, plastik harus dipisahkan menjadi berbagai komponennya. Sebagian besar wadah plastik mempunyai simbol di bagian bawahnya yang menunjukan jenis plastik apakah yang digunakan untuk membuat wadah tersebut. Para pendaur ulang dapat menggunakan simbol ini untuk memisahkan plastik menjadi berbagai kategori untuk memudahkan daur ulang.

Botol PET dan botol susu HDPE mungkin merupakan plastik yang paling sering di daur ulang, tetapi masalah utamanya bukan pada kimia yang terlibat pada proses daur ulang. Masalah utamanya adalah mendorong setiap orang, keluarga, dan dunia usaha untuk mendaur ulang dan mengembangkan suatu cara yang mudah untuk mengumpulkan dan mengelompokkan plastik untuk didaur ulang. Polimer ini terlalu berharga sebagai sumber yang hanya dipendam di tempat pembuangan sampah.

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