Usage: The software can be used without installation for printing labels of chemicals (both English and Chinese).  The chemicals listed in the reference booklet "Classification and Labelling of Dangerous Substances Commonly Used in Industry" can be found in the software.

Sample of printout:

Download: The above software can be downloaded from the following website:

http://www.oshc.org.hk/eng/news/NewsDetail.asp?newsid=212 

or directly from

http://www.oshc.org.hk/download/news/212/537/Chemical.zip (About 8MB)

氨和漂白劑是常見家用清潔劑，可除污漬、消毒、殺菌和除臭。然而，這些化學品的包裝總是有以下的警告：

“注意：不要混合漂白劑和氨清潔劑！”

基本化學

家用漂白液一般是5%的次氯酸鈉溶液，OCl^-(aq)。氨清潔劑是5-10％氨的水溶液，NH₃(aq)，常見例子包括一般家用清潔劑、去蠟劑、窗戶清潔劑和烤箱清潔劑。

把含氯漂白水和含氨清潔劑混合，會生成一個具潛在毒性統稱為氯胺的化合物。這些有毒的氯胺氣體，有辛辣刺鼻性質，可以腐蝕黏膜。有香味的漂白劑都往往妨礙人檢測這些有害氣體自然能力。

化學概念

氨（NH₃）和次氯酸離子(OCl^-)進行反應，氯原子取代氨分子中的一個或多個氫原子，產生3種不同氯胺，也就是說，這些氯胺是氨的衍生物。按照氯的取代程度，這些氯胺分別稱為氯胺（NH₂Cl）、二氯胺（NHCl₂）和三氯化氮（NCl₃）：

OCl^- + NH₃ à OH^- + NH₂Cl

OCl^- + NH₂Cl à OH^- + NHCl₂

OCl^- + NHCl₂ à OH^- + NCl₃

氯胺辛辣和刺激性的氣味經常被誤以為是泳池的「氯氣味」。當消毒用的次氯酸鈉和人們產生含氮的廢物起作用時，會生成氯胺。

在過量氨的環境下，次氯酸鈉離子和氨可生成肼（N₂H₄），肼是另一有毒及具有潛在爆炸性物質：

OCl^- + NH₃ à NH₂Cl + OH^-

NH₂Cl + NH₃ + OH^- à N₂H₄ + Cl^- + H₂O

工業應用

工業上製備肼，即在1907年開始使用的Raschig process，就是利用次氯酸鈉與鹼性溶液中氨的反應。

資料來源 Chemistry Connections（2003），頁182-183。

Attached please find my powerpoint to be used in teaching this section.

Teaching points:

Drug Chemistry PowerPoint (AL) 

1. Teachers may consider to ask the students to indicate the functional groups present in each chemical speices.

2. Note that some are precursor chemicals for some drugs as publicised by the Customs Department. Ask the students why these are the precursor chemicals for some drugs.

你可透過以下新聞透視(2008年10月4日)《毒奶風暴》的片段了解如何添加三聚氰胺在食品中，以造成食品蛋白質含量較高的假象。

http://mytv.tvb.com/news/newsmagazine/3511/533#page-1

http://mytv.tvb.com/news/newsmagazine/3511/756#page-1

 可參考以下網址了解更多三聚氰胺的資料：

三聚氰胺

http://zh.wikipedia.org/zh-hk/%E4%B8%89%E8%81%9A%E6%B0%B0%E8%83%BA

http://en.wikipedia.org/wiki/Melamine

凱氏定氮法

http://zh.wikipedia.org/zh-hk/%E5%87%AF%E6%B0%8F%E5%AE%9A%E6%B0%AE%E6%B3%95

思考題

 1)      計算三聚氰胺(C₃H₆N₆)的氮量。

 2)      根據凱氏定氮法的方法，透過測定氮原子的含量來間接推算

        食品中蛋白質的含量，而蛋白質的平均含氮量為16%。 

       你認為這種方法能否有效測定食品的蛋白質含量？

 3)      試寫出由尿素製備三聚氰胺的化學方程式。

三聚氰胺(思考題)

The concepts involved in the movie clip will be suitable for most AL chemistry students, and will be a bit challenging to NSS chemistry students.  If needed, teachers can provide more guidance for their students.

This experiment is to provide students with learning experience related to organic synthesis.  In particular, students will learn a number of practical skills: heating under reflux, suction filtration and re-crystallisation.  In addition, students have to handle quantitative problems: determining the percentage yield and the limiting reagent of a reaction.  This experiment can be completed in two 40-minute lessons.  The amounts of chemicals required are small. 

Please see the draft documents, in English and Chinese, for details.  Click here to download (updated on 6 Nov 09).

Acknowledgment :

• Dr LL YEUNG and Dr Dennis CHAN, University of Science and Technology
• Ms SC CHU and her team, Hong Kong True Light Middle School
• Ms Anita LEUNG and her team, Ho Fung College (Sponsored by Sik Sik Yuen)
• Mr WC LO and his team, S.K.H. Li Ping Secondary School

Volumetric analysis is the common method in determining the amount of hypochlorite or free chlorine in bleach. From the following website, you can find another suggestion for analysing the chlorine content of swimming pool water or bleach - using a colorimeter (Experiment 9.1). This is a good idea for students to carry out a scientific investigation on analysing chlorine content of swimming pool water or bleach using either instrumental method or quantitative method, or both.

Reference website: http://chemistry.slss.ie/ch_mandatoryexperiments.html

The experimental manual: colorimetric-experiment-on-swimming-pool-water.doc

香港化學家的實踐
日期：9/7/2009 (星期四)
時間：9:30-12:30
地點：九龍塘沙福道19號教育局九龍塘教育服務中心西座4樓演講廳
內容：
1. 光動力治療的展望-香港中文大學化學系盧沛芝教授 [演示檔案]
2. 用於有機發光二極管和太陽能電池的金屬有機功能材料-香港浸會大學化學系黃維揚教授 [演示檔案]
3. 分子美食學-香港科技大學化學系楊霖龍教授 [演示檔案]
課程資料：
http://tcs.edb.gov.hk/main/TDU/ComPreviewForm.asp?CourseID=CDI020080936&LanguageFlat=2&Posted=1&Web=1&Freeze=1

The seminar had been held on 8 June 2009, click here to download the presentation files.

Safe Practices in Chemistry Laboratory (Mr Sam TUNG, SEPO, UST)

Mr Kyle CHAN, Marymount Secondary School

Chemistry Lab Safety.pdf (Mr Raymond FONG, EDB)

The programme was as follows.

- Talk: Safe practices in chemistry laboratory
- Talk: Practices for enhancing safety in practical work for NSS Chemistry
- Experience Sharing: School laboratory design and refurbishment
- Questions and Answers

Infrared spectroscopy: solid sample prep (6:28")

Infrared spectroscopy: liquid sample prep (2:25")



Operation of an IR spectrometer (1:35")

 

Melting Point Determination (4:07")

 

Reactivity of haloalkane (7:02")

Thin Layer Chromatography (3:35")

Source: produced by Dept of Chem, UST with the support of QEF