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Post by Mr Kwok on Mar 10, 2009 4:49:40 GMT -5
Dear everyone, Chemical Bonding is one of my favourite Chemistry topics. Let's start a little discussion here to see how much information we have about this topic. You may wish to use information from your O level journey and/or information which you have found from the internet. In this discussion you could either highlight a misconception or highlight an application of chemical bonding. (Please use blue for "misconception" and "maroon" for application.) Rules: - Each individual can only highlight one misconception or one application at a turn.
- You can add again only if there are 5 other entries after your previous entry.
- If there is a particular misconception or application which you do not understand, you could quote the person's entry for clarification.
To start the ball rolling: Misconception:
A covalent bond is long therefore it is weak.Regards Mr Kwok |
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Post by dangngocdung on Mar 12, 2009 7:54:54 GMT -5
The ionic bond between a magnesium ion Mg2+ and oxide ion O2- in MgO is a double ionic bond.
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Tim K
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Post by Tim K on Mar 13, 2009 8:38:09 GMT -5
Ions pack together in an array of alternating opposite charges to form an ionic lattice.
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clare
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Post by clare on Mar 14, 2009 2:26:20 GMT -5
In pure metals,the positive metallic ions are arranged in layers and can slide over each other when a force is applied.
In alloys, particles of a foreign element disrupt this orderly arrangement, preventing the atoms from sliding,thus increasing the strength of the metal.
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Post by renaldy on Mar 14, 2009 10:47:21 GMT -5
That there are 2 types of covalent bonds A weak covalent bond, which is shown in the arrangement of water molecules held together by weak van der wall forces, and a strong covalent bond, like in the diamond structure
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Post by samuelang92 on Mar 15, 2009 9:38:22 GMT -5
Misconception:
"Covalent bonds must be weak because covalent compounds have low melting points"
This is not true as low melting points would only show that the covelent compound has weak Van der Waals forces of attraction and not weak covalent bonds. In actual fact, the covalent bonds are hard to break. These covalent bonds are also known as intra molecular bonds, which are strong in nature.
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Post by crystal on Mar 16, 2009 4:20:18 GMT -5
Graphite has giant hexagonal planar layers of carbon atoms lying on top of each other. These layers can slide over each other because of the weak van der Waals' forces of attraction. Graphite can then be used in making of pencil leads as it is soft and slippery, allowing the carbon layers to flake off and stick to paper when we write.
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lum76
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Post by lum76 on Mar 16, 2009 5:12:18 GMT -5
A molecule made up of non-polar bonds will not be polar.
Ozone O3 consists of two O-O non-polar bonds but is still polar due to its "Mickey Mouse" shape.
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Post by Mr Kwok on Mar 16, 2009 17:18:00 GMT -5
Great work everyone, lets see if the rest of the class can generate more ideas! For the earlier posters, some of you can post again! =)
In a chemical reaction, when stronger bonds are formed and weaker bonds broken. The reaction is exothermic. When the converse happens, the reaction is endothermic.
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lum76
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Post by lum76 on Mar 17, 2009 8:59:59 GMT -5
Mr. Kwok... A covalent bond is long therefore it is weak. What do you mean by a "long" bond? |
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Post by Mr Kwok on Mar 17, 2009 10:26:30 GMT -5
Mr. Kwok... A covalent bond is long therefore it is weak. What do you mean by a "long" bond? Hi Nicholas, Like measuring the atomic radius, we are actually able to measure the length of the covalent bond. Hence, a long bond means a bond with a long bond length. Interestingly, many people have the misconception that a long bond length results in a weaker bond. This is not true. To determine the strength of a covalent bond, one must first understand what affects the covalent bond, then use these factors to account for the varying strength of the covalent bonds that exist. I think the easiest way to decide whether a statement is a reason or an observation is to classify them as either "cause or effect". Length of a bond and strength of the bond are both examples of effects due to a particular cause. Hence, neither are reasons to each other. =) Mr Kwok |
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Post by Peck Fen on Mar 17, 2009 21:24:18 GMT -5
Ammonia is an ionic compound as it is soluble in water.
Some covalent molecules are polar molecules which can dissolve in water because they form hydrogen bonds with water. Some examples of polar covalent compounds are sugar, ethanol, acetone, carbocylic acids and hydrogen choloride.
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joann
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Post by joann on Mar 17, 2009 23:25:02 GMT -5
Electron pairs are equally shared in all covalent bonds.
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Post by whyeow on Mar 19, 2009 1:13:08 GMT -5
Ice is less dense than water because when water freezes, water molecules form hydrogen bonds with each other to form a crystal lattice. In liquid water each molecule is hydrogen bonded to approximately 3.4 other water molecules. In ice each each molecule is hydrogen bonded to 4 other molecules. The ice structure takes up more volume than the liquid water molecules, hence ice is less dense than liquid water.
lol.
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lyria
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Post by lyria on Mar 20, 2009 5:16:35 GMT -5
In a molecule atoms are arranged at 90 degrees or 180 degrees from each other.
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