Lanthanides

Hi there,

So sorry, was really busy since the start of school this year. You can't imagine...

Anyway, since Tony has requested for Lanthanides, we will have, with no choice, to provide some things about it. To know why Tony is so powerful, ask any 4I '07. Haha.

Now, Lanthanides... these are the f-block elements, see the two rows that look like being 'inserted' into the Periodic Table.

Picture from http://www.dayah.com/

Let us revise... Why is Gp I and II metals called s block elements?

Li 1s2 2s1
Mg 1s2 2s2 2p6 3s2
K 1s2 2s2 2p6 3s2 3p6 4s1

See the pattern? So why Lanthanides are called the f-block?

Anyway, dun want to dwell too much, else many would have headaches. If you are really interested, I've a good website to recommend, very comprehensive. It is a course website from Oxford University Chemistry Department.

Enjoy!!

p.s. they have got some interesting mnemonics to aid you in remembering the sequence of lanthanides. Go check it out. =)

The Quest for Chemistry Continues...

Yoz,

I'm sure some of you are bored with the days of playing WOW, HGL or wat have you. So if you are looking for something to read, here's the right place!

We all know cats have superb vision in the night. However about dogs?

Read up more about night vision in dogs here.
(Picture taken from ScienceDaily.)




Now, how is that Chemistry related? Do you know that we rely on Chemistry to see? Isomerism (what's that for those who have returned all your organic chemistry to me) is important in the Chemistry of vision. Enjoy!










Picture taken from Washington University.

Fats: Good or Bad

Hi,

Some of you are interested in finding out more about Fats. Read these articles about fats:

Good Fats and Bad Fats

Saturated Fats

Qns:

1. What are unsaturated fats?

2. How could we distinguish unsaturated fats from saturated fats? [Use your chemical knowledge!]

*3. What are transfats?

*4. Which are transfats bad and non-transfat better for health?

*You know what it means when we starred a question rite? ><

Polymer: A fascinating research topic

Yoz,

Here are some articles on the recent topic of Polymers which we have covered.

Fascinating Spider Silk - Spider silk is a polymer with many useful properties.

Q1. Which class of polymer is spider silk? Which mechanism of polymerisation is it made from?
Q2. What are the monomers making up spider silk. What functional groups do these monomers contain?
Q3. We have learnt about monomers, dimers and polymers. What is an oligomer? [Advanced material]

Picture taken from National Geographic.

A myriad of potential applications of spider silk are described in the following article: Artificial Spider Silk Could Be Used for Armor, More

Welcome To A New Era In Recycling Of Plastics

Q1. Ionic compounds have high melting point. Why is that so?

Q2. How is it possible to get an ionic liquid? [Advanced material]

Gas Hydrates

Yoz.

Just as we were talking about the gas hydrates, Russia is claiming its rights to them.

Russian Arctic flag planting ridiculed

Picture taken from Channel Newsasia website.

Now, for those interested in finding out more about the gas hydrates, read this:

Gas hydrates - Fuel of the future?

Q1: What are gas hydrates?

Q2: What fuels people's interest in it? (no pun intended)

Q3: As global warming continues, the gas hydrates become more accessible. What social, economic, political and environment issues will it bring?

Picture taken from http://ess.nrcan.gc.ca

Have fun thinking of these questions (and not just mug for ur coming CCTs).

Electrolysis-related old news

Can news be old.... *pondering* Anyway, here's the news (that are old)...

Engineers Forge Greener Path To Iron Production

Basically, researchers at MIT are studying the viability of extracting iron through electrolysis.

Q1. Why do we not use electrolysis to extract iron at the present?
Q2. Why do the article say "Unlike aluminum smelting, however, MOE is carbon-free."? Is C used in aluminium extraction?
Q3. Do you think that electrolysis of iron oxide is really carbon-free?

Current Research Offers Hope For Liver Cancer Patients

If you think this article is out of place, then you are wrong. Researchers at Adelaide University are trying to kill tumor cells using electrolysis.

Two electrodes are used to treat a tumour in the left lobe of a patient's liver. Gas from the electrolysis forms a cluster of bubbles around one electrode. The yellow structure is the divided ligamentum teres.

Picture taken from http://www.adelaide.edu.au/news/image466/liver_segmt2.jpg.html

Q4. What gas do you think is formed at the electrode?
Q5. What are some problems you think we might face with this technology?

So here's the fifth application of electrolysis =P

Please submit your answer to the comments section and not the tag-board. Thanks.

Equilibrium - Le Chatelier's Principle

Yoz, everyone.

This week, we learnt about the Le Chatelier's Principle.

The reason I gave for learning this principle is that understanding and applying Le Chatelier's principle is central to maximizing the yields of desired chemical products in the laboratory and in industry.

However, upon a search on the web, it appears that it is more useful than what we think. Read this:

LE CHATELIER OR BUST?—OR WHY DOOMSDAY SCENARIOS ARE ALWAYS WRONG

Enjoy.

p.s. that's Le Chatelier btw, NOT me ok...

Chemists Strike Gold...

... with new gold catalysts.

Go read this article: Chemists Strike Gold With New Gold Catalysts

It is related to our latest topic on Kinetics. And for those who are interested to find out why Gold is golden in colour, read it too.

On a more light hearted note:

Source: Unknown.

Lesson Objectives for Kinetics

Yoz,

Here's the learning objective for the recently concluded topic.

Of course, not to forget our Boltzmann's distribution curve and using it to explain how increasing temperature or presence of catalyst helps to speed up rate of reaction.

The Old and New Sources of Energy

Yoz,

We have come to an end for the topic of Energetics. Besides knowing about exo and endothermic reactions, we also discussed about alternative sources of energy.

Here's an article discussing the cost of coal on the environment and the global economy.

http://www.sciencedaily.com/releases/2007/05/070504151722.htm

We have talked about using fuel cells as an alternative source of energy. But what is preventing this technology from becoming so widely used? One problem is with the storage of H2. What is being done about this? Read this for an idea.

http://www.sciencedaily.com/releases/2005/09/050907102549.htm

What other ways are possible? Maybe some bright sparks among you could win the next Nobel prize with this. Do contribute your wildest idea in the comments.


The "Hydrogen Tablet". Picture taken from ScienceDaily

All about Steel

Dear all,

Hi. There seems to be some confusion created by the video taken was shown in class. In the video, pig iron snapped at a force of 6 tons, while steel snapped at a force of 8 tons. What do these show?

Actually, we are measuring tensile strength, i.e. the maximum load in tension a material will withstand before fracturing, or the ability of a material to resist being pulled apart by opposing forces. Hence, I would infer that this property is related to brittleness.

From our notes on alloys (Para 5), it was said that 'brittleness increase as the carbon content increases'. This is exactly what is shown in the example above.

To clarify the terms used on metal, here's quite a good resource:
http://www.arcraftplasma.com/metalchar.htm

Actually, if you are seriously interested in finding out more about strength of steel, you could read this article. Basically, it seems to suggest that strength of steel depends not only on carbon content, but also a variety of other factors.

http://www.key-to-steel.com/default.aspx?ID=CheckArticle&NM=11

To find out more about the other factors, here's a link:
http://www.matter.org.uk/steelmatter/metallurgy/6_1.html

Lastly, there is this interesting article that is highly related to our study on Metal extraction and steel making. In summary, MIT is suggesting to make steel through electrolysis. But why are we not doing it? What are the benefits and disadvantages?

http://web.mit.edu/newsoffice/1996/steelmaking.html


Steel wire. Taken from http://en.wikipedia.org/wiki/Steel

Summary of Reactions of Metals

Yoz,

Here's a summary I've gotten from Encarta.

Q1. In class, we have agreed that Hydrogen is placed above Cu since Cu is unable to displace it from the water, steam or acid. However, the observation reported by Encarta is different (see Pb). Why?

Q2. If Hydrogen were less reactive than Fe, why is it able to reduce Fe2O3? What conditions are required for the reduction to take place? What does this tells us about reactivity of Hydrogen? Would we then be able to use carbon to extract reactive metals from their ores?

Please give your comments.


Picture taken from:
http://encarta.msn.com/media_461542064/Reactivity_Series.html

How Batteries work?

Yoz everyone,

So, we have all learnt how to create a battery using a fruit.

Now, Energizer actually has quite an interesting website on the working of Alkaline battery. http://www.energizer.com/learning/howbatterieswork.asp

Please visit the website and discuss in the 'comments' section:
1. What is the cathode of the battery.
2. What is the anode of the battery.
3. What electrolyte is used in the battery.
4. What reactions takes place at each electrode? Give the half equations.
5. How does electrons flow?

In addition, quite a number of you asked how a rechargeable battery works. The same website has a short description of it. You might want to read it too.


The human electrolyte? Do you think we can act as electrolytes?
Picture taken from http://www.exploratorium.edu/snacks/hand_battery.html

More ... Qualitative Analysis

Yoz all,

Hope you are enjoying your hols. I'm sure you have completed your task assigned by Mr Clow Snide right?! If not, you will be banished to his Kingdom (where huh??) when I see you next week... *evil grin*

Anyway, I'm going to start a new discussion about QA.

From our lessons, we have learnt to identify H+, NH4+ and some metal cations based on their reactions with carbonate, zinc, litmus paper, alkalis and lead(II) nitrate. (Can still remember which test is for which ions??!)

If all these tests fail to give us any positive results, then we may conclude that "Group I metal ions may be present". I've told you that the flame test could actually be used to identify the metal ion present.

So here's a link for you to read about flame test:

http://chemistry.about.com/library/weekly/aa110401a.htm

The article states that "the flame test is limited by interference from other brighter colors and by ambiguities where certain different metals cause the same flame color".

Now, my question is: Can we use flame test to positively identify the metal ions? If so how? What is the principle behind this technique?

Let's discuss using the comments function. The one who contributes most to this discussion will get ..........




Picture taken from http://elementy.ru/trefil/36

The picture shows flames of three burning substances, each containing the elements sodium, strontium and boron (from left to right) respectively.