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

Today

My Future Career!!

Since June 1995, I have always wanted to be a pilot and surprisingly, till now, it never changed.

Why I want to be a pilot? Well, mainly I like the idyllic sceneries you get when you fly at....
10000feet:

or 20000feet:

or 30000feetor even 80000feet: Yeah yeah, snap back to reality...
100feet would do:

Apart from that, the real reason is my first and only love is the sky... (Im not kidding).

So, whats a pilot?

Aviators (Pilots) are professionals who posses the ability of increased awareness of their surroundings, maintaining safety standards in an aircraft and commandeers the aircraft to the best of his ability. The aviator assumes the responsibility of all souls onboard as well as the structural integrity of the aircraft in flight. (NASA)

Pretty cheem eh? For better understanding, a pilot is very alert, safety conscious, and the "expert" when it comes to 'who can fly this thing??!!'. He is also responsible for everyone onboard and the aircraft.

What do I need to be one?

Minimum requirement to be a pilot:

Eyesight: less than 500deg

Academic: Degree, Diploma or a full GCE 'A' Level Certificate with passes in English, Maths and Physical Science at 'O' level.

Kinda strict right? And theres no chemistry involved! So what am I doing in ms Jee's class? I guess it might be fun to crawl in the fuel tanks once in a while, getting drenched in parrafin and doing a litmus test to identify impurities...

Overall, the job is perfect for me. Not only do I get to live my dream, I get to see the world and earn big bucks! Life is great huh?

However, the risks are high. Minor setbacks cannot be taken seriously.. For example, a tiny hole in an aircraft's structure.. a little duct tape here and there what could go wrong huh? -All can go wrong.

And Ironically, I like the risks, cus if you reach your destination safe and sound, the sense of achievement is amazing!

How's the job like?

I know all of you out there think that a pilot have to sit in a cockpit full of dials and switches and ask 'how do you manage all that??'. The answer, not all dials and switches are relevant to flying the plane. The ones right in front of you would do!

And on a long-haul flight like from Spore to London (13hrs), what are we doing? Flying the plane of course!! For 13hrs, we fight fatigue and boredom while you guys sleep comfortably! So a little appreciation would be good, or at least provide monopoly or sth for us...

Hence the average pilot would describe his job as long boring hours punctuated by split-second procedures and emergencies. Enjoy the boredom while you can cus when its time to land or an engine fails, you wont have time to ponder over what to do..

Today

Whoa... All this work on math and physics has left chemistry untouched..(especially this blog), and ms Jee is starting to take notice. (Surprised to recieved the email which I just read...hehe).

Okay okay, so my strengths and weaknesses eh? This is supposed to be personal but, oh well:

Strengths:
-Blast Furnace-From Fe2O3 + 3CO -> 2Fe + 3CO2

-Adding coke (carbon) to produce CO gas to reduce Fe2O3 into Fe (above)
C + O2 -> CO2
-Adding limestone (CaCO3) to remove impurities in haematite
CaCO3 -> CaO + CO2
In which CaO reacts with impurities (Silica/Sand) in haematite
CaO + SiO2 -> CaSiO3 + CO2
-And the 3 waste gasses are CO, CO2 and SO2

-Organic Chemistry (excluding macromolecules and polymerisation

4 common homologous series
-Alkanes, General Formula CnH2n+2, Functional Group C-C/C-H
eg. Butane=C4H10
-Alkenes, General Formula CnH2n, Functional Group C=C
eg. Propene=C3H6
-Alcohols, General Formula CnH2n+1OH, Functional Group -OH
eg. Ethanol=C2H5OH
-Carboxylic Acids, General Formula CnH2nO2, Functional Group -COOH
eg. Methanoic Acid=HCOOH

Hydration of alkenes form alcohols
Alcohols + Carboxylic acids = ester (a sweet smelling substsance used in perfumes)

Weaknesses: Atoms, moles and stoichiometry (Im getting better, don't worry...)

Today

Today i learnt...



The lab can be a dangerous place.














Haha, that is if we dont follow precautions!

Lab safety is crucial as there is presence of highly volatile substances (Eg. propane) as well as other elements of malice (Eg. Bunsen burner)

Eating and drinking should also be avoided as my previous chem teacher once said that chlorine gas can react with water, which when consumed.....(something bad will happen)

Apart from safety, we should practice our lab skills so as to be precise and accurate. I learnt that random errors can be reduced by repetition of procedures and observations while systematic errors cannot be reduced as such.

Finally, must remember to express readings according to the D.P. of smallest division of the instrument :)

Today

Learning points for today..

I realised that in most chemical calculations, the amount of substance, mole, can be used for various calculations to determine various quantities since it appears in most of the formulaes.
Eg.
Mol=mass/Mr or Ar
Mol=Volume/molar volume

Hence, problems involving mass, volume, etc., Ill try to look at the amount of substance(mole) first and solve using the abovementioned formulaes or mole ratios.

Today

What ive learnt today?

Well, to better understand questions, find out the problem, which isnt too hard, and the purpose, which IS hard. However, the purpose helps us identify what the question is testing us and help us narrow down the formulaes or concepts involved. Also, we got homework, sienz... must complete by nx week..

Finally, must remember, sulPHate is now sulFate! Haha

Miss Jee say must do this so;

Binary covalent compounds(BNC)
Definition:Binary covalent compounds, which are pure substances that consist of two nonmetallic elements.Eg. H2O, CH4

BNCs can be recognized by their formulas, which contain symbols for only two, non-metallic elements.

Example, N2O3, is a BNC as N, nitrogen and O, oxygen are both non-metals.
The identity of an element can be indicated using the following prefixes with respect to theirsubscript;
1 - mon(o)
2 - di
3 - tri
4 - tetr(a)
5 - pent(a)
6 - hex(a)
7 - hept(a)
8 - oct(a)
9 - non(a)
10 - dec(a)

The second element is indicated by its respective root;
H - hyd
C - carb
N - nitr
P - phosph
As - arsen
O - ox
S - sulf
Se - selen
F - fluor
Cl - chlor
Br - brom
I - iod

Hence N2O3: Dinitrogen trioxide