Archive for October 2016
This one from Hank Green is quite clear 🙂
Girls, this is what I believe, and am squeezing my time doing it. Just like recently bought an interesting magazine “History of Kings and Queens” and spark my interest in Europe history, England in particular.. so you see me digging and watching a lot of relative videos online. (Oh ya, and met the funny John Green with his marvelous Crash Course)
Remember this, and remember me doing the same. And I can do it, so can you. Love.
Power Point: Maths Olympiad-Bases other than Ten
PDF worksheet: MathsOlympiad-Advanced-L19-Bases-other-than-Ten.pdf
I must say what a brilliant idea to explain this using boy bands. And have a good laugh when he equates Bromine, Chlorine, Florine, Oxygen and Nitrogen to One Direction when explaining the Electronegativity.
Still, it’s very fast, and packed with information. But, hey, it’s a crash course, so …
Additional note on ice and liquid water:
Why does ice float?
What other observations or facts are known?
- Because ice floats, we can infer that ice must be less dense than water.
- If water is frozen in a glass jar, the glass jar breaks.
- If a pop can freezes, it will also burst.
- From both of the above we infer that the volume of the ice has increased.
Conclusion: The volume of ice must be greater than the same mass of liquid water. Why does the volume increase?
In liquid water, each molecule is hydrogen bonded to approximately 3.4 other water molecules. In ice, each molecule is hydrogen bonded to 4 other molecules. So ice forms more hydrogen bonds than liquid water. This difference in hydrogen bonding increases the space between each water molecule, thus increasing the volume of ice. Hence ice is less dense than liquid water. This also means ice floats on water.
Take this video from Hank Green as revision as well as learn addition stuff related to chemical bonding such as the Coulomb law. Must say he is fast and I have to watch, pause and repeat a few times to take down all the important notes 🙂
Let’s look into how water bond. Learn the effect of the lone pairs of electron in the bonding.
And the following video explains how the polarity in water molecules covalent bonding creates the intermolecular force called “hydrogen bonding” which is very important and affecting the properties of water we have now.