I was surfing on the internet and came across this short youtube video on Covalent Bonding.

Thought the explaination is simply presented and you may find it beneficial for your learning.

Covalent Bonding is defined as bonding of 2 or more atoms by the sharing of electrons.

PS: This is not my video on youtube, but uh huh..perhaps i should also look into making appropriate videos on Chemistry Concepts in order to help you to learn better.

Q) Since HCL has strong covalent bonds, why is it that they dissociate easily into H+ ions and Cl- ions when put in water?

Answers:

In GCE O Level education, this question is usually not posed. In Junior Collleges, detailed explanation will be given in general chemistry classes.

Suggested Answer:

The hydrogen chloride molecule HCl is a simple diatomic molecule consisting of a hydrogen atom H and a chlorine atom Cl connected with a covalent single bond. Since the chlorine atom is much more electronegative than the hydrogen atom, the covalent bond between the atoms is quite polar. Consequently the molecule has a large dipole moment with a negative partial charge ?- at the chlorine atom and a positive partial charge ?+ at the hydrogen atom. In part due to its high polarity, HCl is very soluble in water (and in other polar solvents).
Upon contact with water, it immediately ionizes, forming hydronium cations H3O+ and chloride anions Cl- through a reversible chemical reaction with the water:
HCl + H2O –> H3O+ + Cl?

The resulting solution is called hydrochloric acid and is a strong acid.

To Your Academic Success in Chemistry,
Sean Chua
Master Trainer @ SimpleChemConcepts.com

Ways to increase interest in Chemistry and Improve your grades be it for GCE O Level Chemistry, ICGSE, IB or IP prorgammes.

Everyday Life Occurences is the KEY!

As i have mentioned earlier, learning Chemistry is easy when you show aptitude and interest in the subject. Chemistry is happening around us everyday – all the phenomenons.

Below i would like to share with you on a Chemistry Phenomenon that i came across in TODAY papers dated 25th Aug 07.

Title: Did Pigeon Poo Weaken Fallen Minnesota Bridge?

I almost LOL when i read the title of this article. Interesting isn’t it. Corny in a way. But after catching my breath and reading through – it is no corny anymore, it is based on scientific knowledge.

Inspectors searching for causes of the collapse of a Minnesota Bridge this month that killed at least 13 people have identified pigeon droppings as a possible factor. It is thought the build-up of Guano over many years could have speeded up the rusting of the steel beams in the eight-lane bridge, which collapsed into the Mississipi River on Aug 1.

Structural engineers had been aware of the problem as early as 1987, when inspectors noted a coating of Guano on the inside of some of the steel girders. Pigeon droppings contain Ammonia and Salt, which, when combined with rainwater, can lead to tiny electrochemical reactions that rust the steel.

“Over a long term, it might in fact cause structural weaknesses.” Mr Neal Langerman, of the prestigous American Chemical Society (ACS) said.

The authorities can point to efforts to contain the problem, when screens were put up to prevent pigeons from nesting in some if the openings in the structure. But the build-up of Guano is thought to have continued on the other parts of the bridge.

Guano is just one of the factors that Inspectors are considering as they seek to prevent a repeat of the catastrophe in other ageing bridges in the United States.

Here is what i call CHEMISTRY – The World of Wonders!

Enjoy,

Sean, Master Trainer
Chemistry Made Easy

On 9/8/07, student wrote:

i have alot of difficulties understanding this two subject..Physics & Chemistry
is dere any easier way to rmb the points?

Hi student,

Learning subjects are like playing games, you need to know the rules of the games in order to play them well with good strategies certainly.

Physics:
- Know definition well
- Know the formulae
- Know about Units conversion
Units conversion will help rmbr Formulae, and in turn, help to rmbr most of the definitions.
This is a skill that some school teachers have ceased to impart.

Chemistry:
- Most Interesting of all 3 Sciences.
- Dont really have to memorise much (except QA for O Level). Rest are just based on simple concepts, and observations in life. Let’s just open our minds and eyes.
- Do not skip simple chapters, bcos they will be the strings to tie up all the “more difficult” chapters. They are impt.
- Need to link them to everyday life. Indeed Chemistry is everywhere around us, if you are aware of it.

Hope this helps. Let me know if you need further assistance.

Sincerely,
Sean Chua

Master Trainer

Chemistry Made Easy