Officially the last post.

3 years have gone by. 3 @%#& years. School has ended and the papers are away. This blog holds memories of the good times, and the shit times, all hidden between posts and comments. Chemistry is a distant memory now. MI is no more. Of all places, MI is the most memorable. Home to all the crap one can muster.

Now, girls and guys go separate ways. Girls to higher education, Guys conscripted to hell. No matter how far apart we may be, we shouldn't lose touch. Facebook is great for this, but it is merely a tool. In our hearts, we must stay together. Life goes on.

This may be officially the last post to mark the end of our course, but the memories endure. Memories, which can be relived or retold. To end 3 years of MI, good luck to all on your future endeavours but remain 09S2, forever undying.

Today

Ideal Gases,

Ideal gases are simply a hypothetical "perfect" gas. They obey all three laws; Boyle's law, Charle's law and Avogadro's law. According to the Kinetic Particle theory of gasses, an ideal gas will have:

-negligible gas particle size as compared to the size of the container

-negligible intermolecular forces

-gas particles that are in constant random motion

-gas particles that participate in perfectly elastic collisions

However, in reality, there is no known gas that have obeyed all of the properties mentioned above. So far, scientists have tried to achieve ideal gas state but only got close. Even the smallest molecule, Hydrogen, deviates from ideal gas behavior.

Since ideal gasses are hypothetical, and no such gas exist, we only study how far a gas deviates from ideal gas behavior. Deviation can be compared by comparing the differences in the properties mentioned above between different gases. E.g. CO2 larger size than H2, hence deviates more.

We can predict properties of gases by using the ideal gas equation: pV=nRT where

p-pressure in Pa

V-volume in m^3

n-amount in mol

R-universal gas constant (8.314)

T-temperature in K

The values obtained from the equation deviates from the empirical value as we assume the gas to be ideal (which its not). Therefore we can only predict.

Today

An Evaluation of what went wrong during promo,

Well, firstly, as we all know it, its the time constraint. This has allowed Mun to beat my pathetic score (damn you Mun). Turns out he had a good strategy; only do questions that you are comfortable with and dont waste time!!!! Also I figured out, if out of time for MCQs, anyhow shade as Ni Chen did (but dont have to shade the whole sheet, its unnecessary Chen...). However, when I looked through the paper, Ive identified a weakness of mine; if it looks weird, just continue cus it might be the right answer. (This happened during Qn 1, Sect B; the redox eqns were right but looked weird so marks lost)

The scores might be displeasing but I managed to complete the entire paper without any help (and of course, more time) so there is nothing to worry about other than time management. Therefore, there is still hope of salvaging whats left of promo 1 and perform super-ultra-god-like for promo 2.

Someone gave me this n its quite funnie,

1. Youre reading my post

2. Now youre saying/thinking thats a stupid fact.

4. You didnt notice that i skipped 3.

5. Youre checking it now.

6. Youre smiling.

7. Youre still reading my post

8. You know all you have read is true.

10. You didn't notice that i skipped 9.

11. Youre checking it now.

12. You didn't notice there are only 10 facts

Haha

Whoo hoo! The holidays have arrived. At last, sufficient time to revise and catch up rather than the jam-packed schooldays where homework is squeezed between dinner and bedtime. Its been a while since theres any activity in this blog so I shall summarize what I am confident and not so confident topics for promo exams.

So far, the only problems Im facing comes from CHEMICAL BONDING. Some of the explanations are still blurred for me. Until I get the glasses of knowledge, I need help. So thats why Im coming down for consultation, that is , after I figured out what to ask.

Today

What ive learnt...

Okay, firstly, I came to class ill-prepared. I had not prepared any notes, whatsoever.. So thats that and no harm done. Correction, major harm done! I had trouble understanding the lesson and was struggling to keep up... But I managed to take down a few notes here and there so I don't get left behind.. Now, after reading something online, I feel a little more educated, haha.
So this is what ive learnt so far(skipping the O lvls stuff so dont be alarmed):

Orbitals

Definition: A region of space where electrons can be found 95% of the time.

There are 4 types of orbitals to be familiar with. They are s, p, d and f

S orbitals are generally spherical in shape. They Exist Singularly

P orbitals are shaped like a cuban eight or dumbell. They exist in threes, Px, Py, Pz. This is because p orbitals align according to the x, y, and z axis (these are the three axes mr Tan drew in class). Hence there are 3, k? Also, p orbitals exist in 2lvl shell onwards as first shell is reserved exclusively for 1s orbital.

d and f orbitals to be continued tommorow, haha.

In addition to orbitals are energy levels or energy shells. The closer the electrons are to the nucleus, the less energy it posseses and vice versa. Hence the innermost shell is the lowest energy shell. The first shell will denote as "1"lvl shell, etc.

So, to denote orbitals, we include the "energy shell number" as the coeffecient and the number of electrons in the orbital group as a superscript. Eg. 1s^2, 2p^6

Take note: Each orbital can hold only 2 electrons!!!

So a 2p orbital will hold six electrons (2p^6)since it exist in threes (refer above) with 2 electrons in each orbital.

A simpler way to visualise orbitals would be using boxes (refer to tutorial given by ms Jee). Remember, each box can only hold 2 electrons!!! The box will represent the orbitals. As shown in the tutorial, qn6, s orbitals exists singularly while p orbitals exist in threes, which satisfies what i said earlier right?

Must remember, s orbitals fills first then p, then d.

Finally, must take note: What used to be "no. of shells" is now "Principal Quantum Shell"

Not bad eh? Can still understand... much better actually..

Today

Supposed to be yesterday...

End points and Equivalence points.

End point

This is a point where the indicator used in the titration experiment changes colour.

Equivalence point

This is the point where the amount of titrant is equal to the amount of analyte in the sample. However, we should not mistake the equivalence point has equal volume of analyte and titrant. This is subjected to the concentration or nature (dibasic, monobasic, etc.) of the titrant or analyte.

Eg. 10cm3 of 1.0mol/dm3 NaOH would need 20cm3 of 0.5mol/dm3 HCl.
or
Eg. 10cm3 of 1.0mol/dm3 H2SO4 would need 20cm3 of 1.0mol/dm3 NaOH

So, when choosing an indicator for titration, the end point of the indicator should be exactly at the equivalence point of the titration experiment (pH 7). Known indicators suitable for titration would be methyl orange or penolphthalein as their end point is at pH 7, the equivalence point.

P.S. Jesslyn, thx again for reminding me again this morning... Haha