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。

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)

You may use the following video clip present in 係咪小兒科 (第23集) in teaching the reaction between acid and carbonate / bicarbonate.

Link: http://mytv.tvb.com/variety/areyousmarterthan5thgrade2/101978/860#page-1

At time duration: 16′46"

The question is as follows:

In an empty bottle containing white vinegar, which of the following substances, upon addition to the bottle, will result with the expansion of the balloon?

A. alum

B. baking powder

C. soda powder

The given answer is C.

What do you think?

Teaching tips

Ask your students to

1. search from the internet the chemical constituent(s) present in alum, soda powder and baking powder; and

2. write appropriate equations to illustrate their explanation.

Through watching TV news and reading news articles of chemistry-related issues, students are guided to relate their chemistry knowledge with daily-life and social affairs. In this activity, students are required to analyse a STSE issue using scientific and logical thinking. Moreover, the activity aims to use daily-life related current affairs to activate students’ interest and consequently encourage students to learn chemistry via reading and writing.

Download worksheet

A project by HKEdCity:
http://edblog.hkedcity.net/scitubechemistry/

Five interesting video clips with worksheets are used to introduce different chemistry concepts.  It is good for visual learners.

Topic:

1. Plastic and Polymerisation

2. Removing colours using chlorine

3. Reactive fluorine

4. Halogens react with iron

5. Comparing alkali metals

 活動目的:

透過收看及閱讀與化學有關的新聞，鼓勵學生將所學的化學知識連繫日常生活及社會時事，並幫助學生在科學、科技、社會和環境的議題上以科學及邏輯性思維分析事情。此外，利用與日常生活相關的時事作主題，引發學生的興趣，從而鼓勵學生從閱讀及寫作中學習化學。

下載工作紙

有沒有聽過這首有趣以及可能是唯一的化學歌曲－元素之歌
Have you ever heard of the most interesting or perhaps the only one chemistry song?

(Source: http://www.youtube.com/watch?v=GFIvXVMbII0)

Lyrics:
There’s antimony, arsenic, aluminum, selenium,
And hydrogen and oxygen and nitrogen and rhenium,
And nickel, neodymium, neptunium, germanium,
And iron, americium, ruthenium, uranium,
Europium, zirconium, lutetium, vanadium,
And lanthanum and osmium and astatine and radium,
And gold and protactinium and indium and gallium, (gasp)
And iodine and thorium and thulium and thallium.

There’s yttrium, ytterbium, actinium, rubidium,
And boron, gadolinium, niobium, iridium,
And strontium and silicon and silver and samarium,
And bismuth, bromine, lithium, beryllium, and barium.

There’s holmium and helium and hafnium and erbium,
And phosphorus and francium and fluorine and terbium,
And manganese and mercury, molybdenum, magnesium,
Dysprosium and scandium and cerium and cesium.
And lead, praseodymium and platinum, plutonium,
Palladium, promethium, potassium, polonium,
And tantalum, technetium, titanium, tellurium, (gasp)
And cadmium and calcium and chromium and curium.

There’s sulfur, californium and fermium, berkelium,
And also mendelevium, einsteinium, nobelium,
And argon, krypton, neon, radon, xenon, zinc and rhodium,
And chlorine, carbon, cobalt, copper, tungsten, tin and sodium.

These are the only ones of which the news has come to Hahvard,
And there may be many others but they haven’t been discahvered.

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

為使學生能安全地透過實驗活動學習，我們有必要適當地提醒學生如何安全地進行實驗，以及實驗潛在的危害。有見及此，我們製作了一些常用的實驗室安全標記，教師可因應個別實驗的需要，自行印製不同尺寸的標記來提示學生，並可參考下圖所示的方式展示這些安全標記。

下載檔案