It's the end of my first semester in NUS. Time flies, really. I could still visualize the me going through orientation camps, living the life of passion.
I shall not waste time blogging about the tiny bits and pieces of my semester 1 experience, because it'll be insanely boring. I can't find inspiration to write them either way.
In summary, the biggest life lesson I learnt in semester 1 is that it pays to be consistent, in schoolwork, at the very least, even though I believe this trend extrapolates to almost everything else that is a process.
So, how did I come across this lesson?
Well, the usual way - By making a mistake. While I would not say that I fared badly for semester 1, I feel that I would have done a lot better if I had been more consistent in the very basic things like doing tutorials(and turning up for them), attending lectures, etc. I feel that I have failed my responsibility as a student as I was not disciplined enough.
But all is not lost. The very fact that I am blogging about this suggest that I have learnt a more valuable lesson than what most of the other students would. What I gained is not only academic knowledge, but knowledge of myself which would accompany me, and enrich me for at least the next 7 semester, or even for the rest of my life.
In this semester, something I want to share with everyone who reads this is - While I lost, I gained. It's not solely about the CAP, but what you make out of this tertiary education. While academic knowledge is valuable, self-discovery is priceless.
Don't lose yourself in search of an 'success'. Don't look back at the end of this phase of your life, and ponder if the only thing different about you then, and four(or three) years ago is your undergraduate degree.
With this, I wish you all the best in finding life's greatest experience(s).
Showing posts with label Education. Show all posts
Showing posts with label Education. Show all posts
Tuesday, December 6, 2011
Sunday, September 25, 2011
Science?
If light cannot pass through opaque objects, and neutrinos are able to, does it not suggest that neutrinos have a mass small than light, and assuming that both light and neutrinos are particles, or waves if we have a primary assumption that particles cannot travel through object.
Wednesday, July 13, 2011
An open letter to the Education Minister from a Secondary 4 student
Letter is quoted from 'An open letter to the Education Minister from a Secondary 4 student.'
This girl is truly wise. She is doing, better, the same things that I did when I was 19, at the tender age of 16.
To notice the flaw of the education system whilst within the education system is no mean feat, definitely. Janelle, I applaud you.
Enough 'captions', here goes:
This girl is truly wise. She is doing, better, the same things that I did when I was 19, at the tender age of 16.
To notice the flaw of the education system whilst within the education system is no mean feat, definitely. Janelle, I applaud you.
Enough 'captions', here goes:
Dear Mr Heng,
I am a Secondary Four student at Nan Chiau High School, and am due to take my O Levels this year. Being shown first-hand what the education system is like, especially from a fairly unflattering point of view, has made me realise much about the education system that I do not like. Of course, I am fully aware that no education system is perfect, yet in the spirit of transformation the PAP has hopefully adopted since the 2011 General Elections, I write this letter to you in the hope that some of these problems with our system will indeed be changed, or if not, at least reviewed.
I speak just for myself, and not for all other graduating students in Singapore when I say this, but I do feel strongly about many methods being employed in secondary schools, especially for graduating classes. For one, I have come to realise the serious emphasis the education system has placed on factual memorisation. Perhaps it is just used in my school, or maybe even a method most autonomous or government schools apply, but based on personal observation, I have come to the conclusion that students are often not taught to ask ‘Why?’
Children are curious and inquisitive, asking their parents questions many parents themselves are not able to answer. As a parent yourself, I believe you can testify to this. Too often, I have heard toddler cousins asking their parents why the grass on my front lawn is green, and how their baby sister was created, or why fruit punch is reddish-pink. I therefore strongly believe that the education system is indeed stifling to a child’s inquisitive and curious mind.
Albert Einstein once said: “The important thing is not to stop questioning. Curiosity has its own reason for existing. One cannot help but be in awe when he contemplates the mysteries of eternity, of life, of the marvelous structure of reality. It is enough if one tries merely to comprehend a little of this mystery every day. Never lose a holy curiosity.” Yet, what is it we are doing to our students today? We are training them not to question, Mr Heng.
I once had to do a Chemistry paper in which I was asked ‘Why?’ for many things, such as ‘Why is carbon a non-metal?’
Perhaps it is just my school’s teaching methods, but for the life of me, I was never once taught why carbon was a non-metal. Since I started with Chemistry in Secondary Three, I learnt that the staircase line divided the Periodic Table into metals and non-metals, and that metals and metals took part in metallic bonding.
That, I believe, is one of the key flaws in the education system. This is a flaw that is not only serious, but also has wide-reaching effects. The most common definition of education is the one provided by the Cambridge dictionary, which states that education is ‘the process of teaching or learning in a school or college, or the knowledge that you get from this’, but I prefer the one found in the students’ favourite dictionary. Education itself, as defined by Dictionary.com, is ‘the act or process of imparting or acquiring general knowledge, developing the powers of reasoning and judgment, and generally of preparing oneself or others intellectually for mature life.”
The beauty of education is to ask ‘Why?’ and have those questions answered. To be aware of knowledge one never knew about. To constantly discover new insights and new things every day, to answer questions lurking in our minds. But far too often, we are taught not to ask why, to just memorise. To get an A1, all we have to do is memorise our textbooks inside out and upside down, and be able to regurgitate them on the very day, tweaking them minimally to answer the questions asked. In the pursuit for grades, I believe we have lost the beauty of education: The ability to ask ‘Why?’
Maybe I’m still a teenager. Still sixteen, still not quite mature in my thinking processes and ways of speech. Maybe I don’t know exactly what type of education system I want, but I know one thing: I want a system where I’m not a product on a factory line, but a real human with an inquisitive mind, always taught to ask and wonder. Memorizing is indeed the fastest way out. Fastest way to good grades, the fastest way out of poverty, the fastest way to a good job and a good salary and a good life. The fastest way to a First World Country. But is it really the best way to educate?
Minister, the purpose of education is to ‘prepare oneself or others intellectually for mature life’. Singapore is a First World Country with developing quartenary industries and a high Human Development Index. It has a stable economy, a thriving political landscape and top-notch healthcare systems. No longer can we adopt the same methods it took us to get here. Instead, what the country needs is more thinkers, more creators. People who dare to ask ‘Why?’ and ‘Why not?’. People who are not slaves to change, but create the change. How do we train the leaders of the nation, if many of our brightest young minds are not bright because they can think, but are bright simply because they know how to maneuver their way around school exams and the education system? It is no surprise then, that many of our local policies are all recycled from those of other countries. They lack imagination and creativity, because it is my deep-set belief that other than curiosity, those are the other things the local education system kills.
My friends are constantly telling me that Singapore has no talent. They are constantly swooning over foreign celebrities, actors and actresses, but in comparison, the support and fanbase for our own local talents are negligible, save for a few. I do not believe that Singaporeans lack talent. In fact, I truly believe Singaporeans are a talented bunch. Art, music, dance, you name it, I can name someone who’s good at it. So what is the problem here, you may ask. The problem is that Singaporean youths are often not taught as individuals with separate talents, but as a collective who are all the same. Often, we suppress our own natural talents for what the education system wants. I have had so many Chemistry and Biology answers marked completely wrong just because I used my own words to express the same idea. ‘Cambridge wants this, so we will give them this’ appears to be the mindset of most of the teachers, who throw us model answers to be memorised. We cannot change the markers at the University of Cambridge, but I am sure you would agree with me that this is not the way to educate youths. Many times, in English, I have been told to follow a certain structure and certain format for even free writing tests. Youths are brimming with creativity and fresh ideas, but we lack that same outlet to express them. Why do you think social networking is such a crazy trend? Social networking gives students a voice that the education system never gave them.
How do we cultivate talent in this manner, by not giving youths a voice? By memorizing tons and tons of model answers and essays to be submitted? In this way, the education system is sending a message to Singaporean youths that it is not wrong to have a voice, but it is wrong to use this voice in the system of education. What it does not realise is that it is the education system that is supposed to give Singaporean students their voice! By educating students, we are giving them the ability and knowledge to speak their minds, yet take this privilege from them away all at the same time.
Is this really what education is? Stifling voices in favour of appeasing examiners, memorizing facts to get that A1, yet all of these are forgotten by the time we start work?
Call me naive, because I am still young, but I believe an education is not about imparting facts and figures and making students digest it all. It’s about shaping a mindset. Creating a person. Nurturing what God gave each one of us. I fear that in the pursuit for the Singaporean Dream, we have lost the initial purpose of education: to create a person, who is opinionated and articulate and creative and imaginative. Who is not afraid to think out of the box and come up with new ideas and policies.
We may be a First World Country, but if our education system still holds the belief that we are in a Second or Third World Country, and need to furiously cram facts in our head to get out of the cycle of poverty fast, then we will never truly raise First World leaders. Leaders who can think about the solution to an exact problem, and not recite whatever they learnt in their political science or economics courses in university.
—
Another gaping flaw in the education system is the premise of character development. From the way it is taught in schools, it often feels like schools are introducing character development just purely for the sake of it, and not for inculcating values important to working life.
Mr Heng, we are taught Civics and Moral Education from a FILE, and from TEXTBOOKS. We are given CME EXAMS. Surely you would agree this is not the way to go about teaching values? Values cannot be taught, so the education system tries to force it down our throats by teaching us morally-correct behaviour.
Since Social Studies in primary school, we have been fed the system’s easy way out. Instead of actually having values instilled into us, we are taught to give morally-correct answers. We are taught to help old ladies cross roads when they look like they need assistance. Though the last sentence may be a bit of an exaggeration, one cannot deny that it is true. Character is not the knowledge that we should help the old lady cross the road, but the actual act of helping her do it.
The sad but true reality is that most teenagers know that the old lady needs assistance, but would rather continue checking Facebook statuses and giving Twitter updates on their smartphones rather than going over and helping the poor soul.
Granted, who am I to make a generalisation and say that all teenagers are this way? I know that there are teenagers and youths out there who are truly compassionate, who would truly go out of their way to help, but I have no arguments in my bag of tricks to argue for the stand that this behaviour is taught by Civics and Moral Education lessons in schools. Rather, more often than not, it is good parenting that leads a child to do so, not CME lessons.
Teachers often ‘eat up’ our CME lessons to have their own lessons, for one. Though this may not be a commonplace occurence, it happens extremely often for graduating classes when teachers are rushing to finish up the syllabus. Again, the system sends out another message: As long as you can get all A1s for your O levels, your character does not matter.
I am sure this is not the intended message, but it is certainly what most of us are hearing. The common mentality is ‘So what if you have a good character? You’re failing most of your subjects.”
I find this rather peculiar, because I for one have always found that with a strong character, good grades come naturally afterwards. With self-discipline and self-motivation, a student can certainly get good grades. Thus, character development should in fact be more important than academic education, because after all, an education is not about pure academics. Instilling values in a child is certainly an important part of preparing them for maturity, for maturity does not come with grades, but with wisdom and growth no amount of midnight-oil-burning can develop.
—
As a Secondary Four student, I experience first-hand the ugliness of the flaws the education system has. In fact, I spent one hour and forty-five minutes writing you this letter. Though I am not sure if you will ever get to read it ever in this lifetime, but this is something that I believe in. I believe in being the change I want to see in the world, or at least in my environment, as cliched as that sounds. Every one else will tell me that this is a waste of time, because I have Preliminary examinations next week and I could have been studying instead of typing this long Facebook note out.
This is the type of education system the Ministry of Education’s policies have cultivated. A system where fighting for things one believes in are seen as a ‘waste of time’, where reading anything non-school-related is seen as yet another waste of time. Is this the type of education a First World Country should have, one where students’ thoughts and abilities to express themselves are confined within the front and back cover of their textbooks, where it is better to be passive and just study hard under the system than fight to change it and waste one’s time, where having your own thoughts is a liability.
Have we lost the true meaning of education somewhere in the paper chase, buried under all the degrees and diplomas and paychecks? Or were we lost all along as to what education truly means?
I have not given up hope that there is still space for change. I have not submitted myself to accepting that ‘this is the Singapore system and I cannot do anything about it’. I am fighting for the changes I want to see in the best way that I can, because I believe that someday, my children will be educated in such a way that they are taught to never stop asking, and to always care about the people around them. I believe that you have the power to make these changes happen, and if not, at least a thorough review of the policies made by your predecessors.
Thank you very much for your time.
.
Janelle Lee
To the rest of you who actually shares similar sentiments with her, maybe it's time to 'unstuck' yourself from the education system and truly learn what it have to offer you; if they don't make it better for us, the least we could do is to make it better for ourselves. Be the change.
Learn, not know.
Monday, May 30, 2011
Thursday, May 26, 2011
Conformity.
In our competitive society critical of anomalies, many succumb to the social pressure to conform. Coupled with an education that is largely exam-based, we are losing a bit of ourselves and becoming a bit of others every year. After all, conforming seems to be working well; We do not get singled out and frowned upon.
But take a step back and look at our situation - In our quest after the tangibles, have we forgotten about the intangibles? Society consensus have decided that leading a happy and fulfilling life is not as important than being affluent. It seem to say that it is only normal to lose yourself to please others. How sad is this.
Ever heard of the word 'slaves'? I don't think we are really that different from them.
If you haven't realized, the worst part of this phenomena is losing yourself, along with the ability to think for yourself.
If we merely conform and do not exercise due discretion, we will be not much different from programmable robots.
There may be a time where robots are created in the image of humans, just as we are created in the image of God. When that day comes, would we then be obsolete?
Maybe it's time to question ourselves of what really matters in life.
Maybe it's time to sit back and enjoy the beauty of life.
Side note #1: Have our education system been too obsessed with meeting key indicators of a good education system? It seem that MOE's move to 'attract' foreign talents is to meet one of the indicator which is the number of foreign students attracted to study in the university. And we question why we do not produce graduates akin that of the Ivy League.
Side note #2: Is our society and economy too obsessed with meeting key indicators too?
But take a step back and look at our situation - In our quest after the tangibles, have we forgotten about the intangibles? Society consensus have decided that leading a happy and fulfilling life is not as important than being affluent. It seem to say that it is only normal to lose yourself to please others. How sad is this.
Ever heard of the word 'slaves'? I don't think we are really that different from them.
If you haven't realized, the worst part of this phenomena is losing yourself, along with the ability to think for yourself.
If we merely conform and do not exercise due discretion, we will be not much different from programmable robots.
There may be a time where robots are created in the image of humans, just as we are created in the image of God. When that day comes, would we then be obsolete?
Maybe it's time to question ourselves of what really matters in life.
Maybe it's time to sit back and enjoy the beauty of life.
Side note #1: Have our education system been too obsessed with meeting key indicators of a good education system? It seem that MOE's move to 'attract' foreign talents is to meet one of the indicator which is the number of foreign students attracted to study in the university. And we question why we do not produce graduates akin that of the Ivy League.
Side note #2: Is our society and economy too obsessed with meeting key indicators too?
Wednesday, September 17, 2008
the arrival of the last prelim paper
tmr's physics mcq, last paper for prelims. finally, can liberate myself from studying and PLAY. hahha.
45 more days to a levels after the paper tomorrow. well, one step towards the end of the prelims brings us one step closer to A levels.
anyway, i was doing some physics paper, then wanted to clarify some concepts. so went online to check.
here they are:
Population inversion
More atoms in the higher energy level than the lower energy levels.
Rankine scale
It starts at 0R at -273°C, like the Kelvin scale. However, one unit of Rankine corresponds to that of one unit of Fahrenheit, unlike one unit on the Kelvin scale which corresponds to one unit of degree Celsius.
Laser pumping
A mean of transferring energy to a system for it to gain energy, which can help the system obtain population inversion
Optical pumping
This is a subset of laser pumping, which transfer light energy to the system.
Heisenberg uncertainty principle
In locating a unit of matter, it is uncertain to a inversely proportionate uncertainty in the momentum provided, due to inaccuracy in measurement, vice versa. This uncertainty is irregardless of experimental set-up, and the proportionality constant is
/2.
Carbon dioxide laser
This is one of the first form of laser to be discovered, and is still one of the most useful due to its high power and efficiency. Basically, this is just another form of laser. (The common one we hear about is the He-Ne Laser.)
Maser
Laser is a subset of this, even though the acronym suggest that it only produce the microwave wavelength of the electromagnetic spectrum, which is not true.
click here to see a picture of a hydrogen maser *It's really cool
Hydrogen Maser
A form of MASER
Basically, this means that even electromagnetic radiation, e.g. light, will gain and lose energy when they move in a gravitational field. It's like how you would expect masses to change in kinetic energy(KE) when you allow them to fall freely. Electromagnetic radiation have higher energy in a lower gravitational field compared to that in a higher gravitational field. Likewise, you would expect masses to have higher KE after they have moved from a region of higher gravitational field to smaller gravitational field. (Gravitational potential energy is converted to kinetic energy in the case of the mass.)
well, maybe if you are doubtful about whether your concepts are exactly right, go check them out. don't bother with the equations though, unless you wanna take physics to uni. guess it's not required for us to know their equations at our level of education.
Interesting reads
-LASER is the acronym of Light Amplification by Stimulated Emission of Radiation.
-When hydrogen maser is used as a clock, it will have an uncertainty of 1 second every 63million years
-an atom with electrons in the same spin have more energy than one with opposite spins.
*I'm wondering what's a ruby maser though, could not gather much information about it.
45 more days to a levels after the paper tomorrow. well, one step towards the end of the prelims brings us one step closer to A levels.
anyway, i was doing some physics paper, then wanted to clarify some concepts. so went online to check.
here they are:
Population inversion
More atoms in the higher energy level than the lower energy levels.
Rankine scale
It starts at 0R at -273°C, like the Kelvin scale. However, one unit of Rankine corresponds to that of one unit of Fahrenheit, unlike one unit on the Kelvin scale which corresponds to one unit of degree Celsius.
Laser pumping
A mean of transferring energy to a system for it to gain energy, which can help the system obtain population inversion
Optical pumping
This is a subset of laser pumping, which transfer light energy to the system.
Heisenberg uncertainty principle
In locating a unit of matter, it is uncertain to a inversely proportionate uncertainty in the momentum provided, due to inaccuracy in measurement, vice versa. This uncertainty is irregardless of experimental set-up, and the proportionality constant is
/2.Carbon dioxide laser
This is one of the first form of laser to be discovered, and is still one of the most useful due to its high power and efficiency. Basically, this is just another form of laser. (The common one we hear about is the He-Ne Laser.)
Maser
Laser is a subset of this, even though the acronym suggest that it only produce the microwave wavelength of the electromagnetic spectrum, which is not true.
click here to see a picture of a hydrogen maser *It's really cool
Hydrogen Maser
A form of MASER
Rømer scale / Réaumur scale
Just other temperature scales.
Gravitional RedshiftBasically, this means that even electromagnetic radiation, e.g. light, will gain and lose energy when they move in a gravitational field. It's like how you would expect masses to change in kinetic energy(KE) when you allow them to fall freely. Electromagnetic radiation have higher energy in a lower gravitational field compared to that in a higher gravitational field. Likewise, you would expect masses to have higher KE after they have moved from a region of higher gravitational field to smaller gravitational field. (Gravitational potential energy is converted to kinetic energy in the case of the mass.)
well, maybe if you are doubtful about whether your concepts are exactly right, go check them out. don't bother with the equations though, unless you wanna take physics to uni. guess it's not required for us to know their equations at our level of education.
Interesting reads
-LASER is the acronym of Light Amplification by Stimulated Emission of Radiation.
-When hydrogen maser is used as a clock, it will have an uncertainty of 1 second every 63million years
-an atom with electrons in the same spin have more energy than one with opposite spins.
*I'm wondering what's a ruby maser though, could not gather much information about it.
Saturday, September 6, 2008
STUDY STUDY
okay, today woke up at 2. supposed to wake up at 8-9am to study la. but then i wake up, off my alarm, and went back to sleep. hhahah.
luckily, i did a little bit of chem today la. nothing much with the papers. but here's 2 questions i'll like to ask:
1: 0.5Cl2(g)------------------>Cl(g)
ΔHat(Cl) OR ΔHat(Cl2)
2:Will you get H2N-C6H4-COOCH(CH3)2 when you reduce O2N-C6H4-COOCH(CH3)2 with H2 gas with Pt catalyst.
ah, help me out with these questions if you know the answer. haah. thanks
anyway, i'm going to CHANGI AIRPORT to study now. hope i'll be able to be SUPER SUPER SUPER productive. hahah. i better get going soon. later i late. hahaha. byebye everybody.
HAPPY MUGGING. 2 DAYS MORE TO PRELIMS.
EDIT NEW!
i found out the answers to the 2 questions alr.the answer to the first question is ΔHat(Cl), and the answer to the 2nd is yes. cause reduction of benzene ring will not occur because the only way to reduce a benzene(that i know of) is to heat H2 gas at a temp of 450K and 10atm, over a Ni catalyst, forming a cyclohexane. therefore, in question 2, benzene ring will not be reduced, and you will only reduce the nitro group, getting a amine group.
ah, i was reading and i found out that aminophenol is the breakdown product of paracetamol.
found here
luckily, i did a little bit of chem today la. nothing much with the papers. but here's 2 questions i'll like to ask:
1: 0.5Cl2(g)------------------>Cl(g)
ΔHat(Cl) OR ΔHat(Cl2)
2:Will you get H2N-C6H4-COOCH(CH3)2 when you reduce O2N-C6H4-COOCH(CH3)2 with H2 gas with Pt catalyst.
ah, help me out with these questions if you know the answer. haah. thanks
anyway, i'm going to CHANGI AIRPORT to study now. hope i'll be able to be SUPER SUPER SUPER productive. hahah. i better get going soon. later i late. hahaha. byebye everybody.
HAPPY MUGGING. 2 DAYS MORE TO PRELIMS.
EDIT NEW!
i found out the answers to the 2 questions alr.the answer to the first question is ΔHat(Cl), and the answer to the 2nd is yes. cause reduction of benzene ring will not occur because the only way to reduce a benzene(that i know of) is to heat H2 gas at a temp of 450K and 10atm, over a Ni catalyst, forming a cyclohexane. therefore, in question 2, benzene ring will not be reduced, and you will only reduce the nitro group, getting a amine group.
ah, i was reading and i found out that aminophenol is the breakdown product of paracetamol.
found here
Wednesday, August 27, 2008
Covalent vs Ionic Bonds, Which is Stronger?
okay, first to start out, a precise answer would be that covalent bonds is stronger. But like all knowledge aquisition, one should be looking for the most accurate answer, and not the most precise answer.
also, one must understand that in comparing items, you cannot use specific examples, simply because you're assuming that there's a trend in the subjects used, and this assumption is VERY likely to fail, especially in the atomic world. basically, this is also the reason why you dont use specific terms to determine if a sequence is an A.P or a G.P, you need to use induction methods to prove that your results is consistent with all the terms.
there's a proposal of theory that covalent bonds is stronger than ionic bonds. Why? Solely because the melting/boiling points of diamond is the highest. Does this make any sense? In my opinion(as with many other scientists), it don't, at all. Why? simply because like all proofs, how sure are you that this trend is held by all covalent and ionic substances? Hence, using diamond as the hardest/most thermally stable substance is not a valid argument in trying to show that a covalent bond is stronger than an ionic bond.
to push my argument that you cannot compare the bonds, here's a few reasons.
Firstly, the theory of a covalent of ionic compound is dependent on the difference in electronegativity between compounds. In reality, NO substance is purely covalent or purely ionic. It's a theory, just like your perfect competition is economics theory. Put simply, the covalent or ionic character of a bond is a continuum, but not discrete. Hence, when you compare a trend of strength of covalent or ionic bond, how are you, then, able to take into account the measure of ionic characteristic in a covalent bond, or the covalent characteristic in an ionic bond?
Secondly, the energy required depends on HOW you break the bond.(Common Examples are: homolytic cleavage, or heterolytic cleavage.) Basically, if you want to separate two non-polar atoms(C and H), you have to simply break the bonds in between. However, if you want to have a net transfer of electrons(heterolytic cleavage), you will need more energy to ionise the electron from one atom, and for the other atom to accept the electron. So, the energy required to break a covalent or ionic bond depends on the type of cleavage of the bonds.
Thirdly, it depends on the phase of your substance when you break the bonds. Ionic bonds tend to require a lower energy for bond-breaking in polar substances such as water, due to the formation of ion-dipole bonds between the ionic compound and water molecules, and this formation of bonds will weaken the ionic bonds between the ionic compound, hence a lower energy is required to break the bonds. Covalent compounds, even when dissolved in a solvent, wouldn't be affected any more than that of ionic compounds. Simply because their bonding is not affected to the same extent of that of ionic bonds.
Fourthly, the energy required to break either covalent or ionic bonds is also dependent on the nature of the substituents of the atoms involved. For example, electron donating substituents will strengthen the bonds in between by providing more electrons, which fundamentally forms the bond.
Fifthly, to even conclude the trend that bond strength is dependent on the difference of electronegativity between the atoms is not valid. Here's an example of anomaly in the trend.
Li-F:1017kJ/mol(Difference in Electronegativity:3.0)
Li-Cl:828kJ/mol(Difference in Electronegativity:2.8)
Li-Br:787kJ/mol(Difference in Electronegativity:1.8)
The examples seem to follow a trend where the energy required to break the bond is dependent on the difference in electronegativity. However, as this example moves on, here's an anomaly.
Mg-O:3890kJ/mol(Difference in Electronegativity:2.3)
Hence, even such a strong trend used to explain various chemistry concepts do not survive, when they are subjected to closer scrunity.
Sixthly, the comparison of melting/boiling point of a substance of compounds do not show how strong the covalent or ionic bond is. Simply because some covalent substance like N2 and O2 forms triple bonds and double bonds respectively, while F2 forms a single bond between atoms.
Which value, of covalent bonds, will you then use for comparison?
Seventhly, how do one determine whether a bond between atoms is covalent or ionic? Covalent bonds are usually defined as the bond between atoms of electronegativity difference of less than 1.5, while ionic bonds are usually defined as the bond between atoms of electronegativity difference of more than 2. But the question is, how accurate is this definition? Why, then, is the bond between Na and Br atoms considered ionic, when the electronegativity difference is only 1.9. Why, then, is the bond between H and F atoms considered covalent, when the electronegativity difference is 2.9? So, how are we able to compare two categories of items, when we cannot even distinguish the dividing line clearly?
Therefore, unless you are able to get a clear formula to determine the strength of a bond, regardless of the type of bonding, you will NOT be able to compare the strength of a covalent and an ionic bond.
Lastly, the only accurately way we are able to compare whether a covalent and ionic bond is stronger is to have a substance that can exist in both covalent and ionic states. However, unfortunately, such a substance do not exist. Hence, what grounds, then, do we have for comparison?
If you think a little deeper, there exist a fair share strong and weak covalent and ionic bonds. This means that if we are to the strength of covalent bonds with the strength of ionic bonds between various compounds, some covalent bond strength would be higher than that of ionic bond, but the reverse holds true. Therefore, this question do not really make any sense.
To digress a little, here's a bit of interesting information that i found on the web:
1:the strongest of the weak bonds(hydrogen bonding, pd-pd bonds, id-id bonds) can also be stronger than the weakest of the strong bonds(covalent or ionic bonds).
This is unlike what we learn in A levels chemistry, where we are told that if the boiling point of a molecule is low, it's held by weak forces of attraction, and vice versa. Apparently, now we know that when the boiling point is low, it can also be held by strong forces of attraction.
2:Ionic bonds are around 80 times weaker when dissolved in water.
Basically, in the A' level syllabus, we're learning that it forms ion dipole bonds with the water molecules, and breaks the ionic bond between the ions, hence energy required is not used to break the ionic bonds, but the ion dipole bonds which are about 80 times weaker.
Sources:
So, maybe this is the time for you to think about the reason why you're studying. So that you can pass your major examinations to secure a well-paying job in the future? or maybe to not let the people who pinned hopes upon you down. or maybe, is it even that you yourself don't know why you are studying and acquiring knowledge.
Now, answer the question, why do you study?
also, one must understand that in comparing items, you cannot use specific examples, simply because you're assuming that there's a trend in the subjects used, and this assumption is VERY likely to fail, especially in the atomic world. basically, this is also the reason why you dont use specific terms to determine if a sequence is an A.P or a G.P, you need to use induction methods to prove that your results is consistent with all the terms.
there's a proposal of theory that covalent bonds is stronger than ionic bonds. Why? Solely because the melting/boiling points of diamond is the highest. Does this make any sense? In my opinion(as with many other scientists), it don't, at all. Why? simply because like all proofs, how sure are you that this trend is held by all covalent and ionic substances? Hence, using diamond as the hardest/most thermally stable substance is not a valid argument in trying to show that a covalent bond is stronger than an ionic bond.
to push my argument that you cannot compare the bonds, here's a few reasons.
Firstly, the theory of a covalent of ionic compound is dependent on the difference in electronegativity between compounds. In reality, NO substance is purely covalent or purely ionic. It's a theory, just like your perfect competition is economics theory. Put simply, the covalent or ionic character of a bond is a continuum, but not discrete. Hence, when you compare a trend of strength of covalent or ionic bond, how are you, then, able to take into account the measure of ionic characteristic in a covalent bond, or the covalent characteristic in an ionic bond?
Secondly, the energy required depends on HOW you break the bond.(Common Examples are: homolytic cleavage, or heterolytic cleavage.) Basically, if you want to separate two non-polar atoms(C and H), you have to simply break the bonds in between. However, if you want to have a net transfer of electrons(heterolytic cleavage), you will need more energy to ionise the electron from one atom, and for the other atom to accept the electron. So, the energy required to break a covalent or ionic bond depends on the type of cleavage of the bonds.
Thirdly, it depends on the phase of your substance when you break the bonds. Ionic bonds tend to require a lower energy for bond-breaking in polar substances such as water, due to the formation of ion-dipole bonds between the ionic compound and water molecules, and this formation of bonds will weaken the ionic bonds between the ionic compound, hence a lower energy is required to break the bonds. Covalent compounds, even when dissolved in a solvent, wouldn't be affected any more than that of ionic compounds. Simply because their bonding is not affected to the same extent of that of ionic bonds.
Fourthly, the energy required to break either covalent or ionic bonds is also dependent on the nature of the substituents of the atoms involved. For example, electron donating substituents will strengthen the bonds in between by providing more electrons, which fundamentally forms the bond.
Fifthly, to even conclude the trend that bond strength is dependent on the difference of electronegativity between the atoms is not valid. Here's an example of anomaly in the trend.
Li-F:1017kJ/mol(Difference in Electronegativity:3.0)
Li-Cl:828kJ/mol(Difference in Electronegativity:2.8)
Li-Br:787kJ/mol(Difference in Electronegativity:1.8)
The examples seem to follow a trend where the energy required to break the bond is dependent on the difference in electronegativity. However, as this example moves on, here's an anomaly.
Mg-O:3890kJ/mol(Difference in Electronegativity:2.3)
Hence, even such a strong trend used to explain various chemistry concepts do not survive, when they are subjected to closer scrunity.
Sixthly, the comparison of melting/boiling point of a substance of compounds do not show how strong the covalent or ionic bond is. Simply because some covalent substance like N2 and O2 forms triple bonds and double bonds respectively, while F2 forms a single bond between atoms.
Which value, of covalent bonds, will you then use for comparison?
Seventhly, how do one determine whether a bond between atoms is covalent or ionic? Covalent bonds are usually defined as the bond between atoms of electronegativity difference of less than 1.5, while ionic bonds are usually defined as the bond between atoms of electronegativity difference of more than 2. But the question is, how accurate is this definition? Why, then, is the bond between Na and Br atoms considered ionic, when the electronegativity difference is only 1.9. Why, then, is the bond between H and F atoms considered covalent, when the electronegativity difference is 2.9? So, how are we able to compare two categories of items, when we cannot even distinguish the dividing line clearly?
Therefore, unless you are able to get a clear formula to determine the strength of a bond, regardless of the type of bonding, you will NOT be able to compare the strength of a covalent and an ionic bond.
Lastly, the only accurately way we are able to compare whether a covalent and ionic bond is stronger is to have a substance that can exist in both covalent and ionic states. However, unfortunately, such a substance do not exist. Hence, what grounds, then, do we have for comparison?
If you think a little deeper, there exist a fair share strong and weak covalent and ionic bonds. This means that if we are to the strength of covalent bonds with the strength of ionic bonds between various compounds, some covalent bond strength would be higher than that of ionic bond, but the reverse holds true. Therefore, this question do not really make any sense.
To digress a little, here's a bit of interesting information that i found on the web:
1:the strongest of the weak bonds(hydrogen bonding, pd-pd bonds, id-id bonds) can also be stronger than the weakest of the strong bonds(covalent or ionic bonds).
This is unlike what we learn in A levels chemistry, where we are told that if the boiling point of a molecule is low, it's held by weak forces of attraction, and vice versa. Apparently, now we know that when the boiling point is low, it can also be held by strong forces of attraction.
2:Ionic bonds are around 80 times weaker when dissolved in water.
Basically, in the A' level syllabus, we're learning that it forms ion dipole bonds with the water molecules, and breaks the ionic bond between the ions, hence energy required is not used to break the ionic bonds, but the ion dipole bonds which are about 80 times weaker.
Sources:
- Newton source 1
- Newton source 2
- MadSci network
- WikiAnswers(not very good, though)
So, maybe this is the time for you to think about the reason why you're studying. So that you can pass your major examinations to secure a well-paying job in the future? or maybe to not let the people who pinned hopes upon you down. or maybe, is it even that you yourself don't know why you are studying and acquiring knowledge.
Now, answer the question, why do you study?
Physics knowledge
when to use fleming's left hand rule, and when to use fleming's right hand rule?
simply put,
Fleming's left hand is used for a current carrying conductor.
Fleming's right hand is used for generators.
well, some people have talked about alternatives to determine when to use your right hand rule.
they say:use your right hand rule when you're trying to find an induced current. well, i dont THINK it's wrong. so, if it helps you remember, then do it that way.
like always, site reference is:
Fleming's Left Hand Rule
Fleming's Right Hand Rule
simply put,
Fleming's left hand is used for a current carrying conductor.
Fleming's right hand is used for generators.
well, some people have talked about alternatives to determine when to use your right hand rule.
they say:use your right hand rule when you're trying to find an induced current. well, i dont THINK it's wrong. so, if it helps you remember, then do it that way.
like always, site reference is:
Fleming's Left Hand Rule
Fleming's Right Hand Rule
chemistry knowledge
okay. this is some basic knowledge about chemistry.
firstly, ethanamine is a gas at room temperature, and like all amines, it's alkali
this information is used to solve for compound I for question 9 from the deductive questions worksheet the teachers gave for revision.(the gas evolved is NOT ammonia, but ethanamine.)
secondly, METHANOIC ACID gives a positive test with tollen's reagent.(even though this clash with our knowledge that tollen's reagent only react with aldehydes, just note the exceptions. also, it reacts with 1-alkynes.)
this is used to solve the deductive question of the acidic product after hydrolysis of the first compound.(question 4a from the LAST chem test, i think paper 3, the one returned unmarked.)
that's about all. of course, i have my sources to cross refer to, to prove that these are reliable knowledge. here they are
http://en.wikipedia.org/wiki/Tollens%27_reagent
http://en.wikipedia.org/wiki/Amine#Physical_properties
firstly, ethanamine is a gas at room temperature, and like all amines, it's alkali
this information is used to solve for compound I for question 9 from the deductive questions worksheet the teachers gave for revision.(the gas evolved is NOT ammonia, but ethanamine.)
secondly, METHANOIC ACID gives a positive test with tollen's reagent.(even though this clash with our knowledge that tollen's reagent only react with aldehydes, just note the exceptions. also, it reacts with 1-alkynes.)
this is used to solve the deductive question of the acidic product after hydrolysis of the first compound.(question 4a from the LAST chem test, i think paper 3, the one returned unmarked.)
that's about all. of course, i have my sources to cross refer to, to prove that these are reliable knowledge. here they are
http://en.wikipedia.org/wiki/Tollens%27_reagent
http://en.wikipedia.org/wiki/Amine#Physical_properties
Monday, August 11, 2008
consequences of BOP deficit
basically, i got a major part of my information here
http://tutor2u.net/economics/revision-notes/a2-macro-balance-of-payments-deficits.html
and the rest from ms sarah ee
here are my summarised points
BOP deficit will:
1:greatly reduce the investment and consumption confidence due to poor economic outlook, and if the country decides to increase interest rates to persuade the investors to keep investing in the economy, it'll have a negative effect on domestic investment and consumption.
2:make future growth difficult as their earnings would have to be used to repay the money borrowed previously.
3:cause a fall in employment as there is excessive foreign product consumption which results in a fall in domestic products demand and will hence result in a fall in domestic output and hence employment
4:cause the borrowing country to be influenced strongly by the lending country, both politically and economically
5:cause a downward pressure on exchange rates as there is a large supply of the currency in the foreign exchange market which may lead to imported inflation due to relatively more expensive imports, and may lead to a rise in interest rates in order to curb the inflation. while declining currency will reduce the relative price of exports and hence increase value of exports, there would be negative effect on demand, output and employment.
i hope these points will help you in your studies of BOP, because the consequence of BOP deficit is often solely "the country will be in debt", with no explanation. you can tag if you find this post useful in your studies.
http://tutor2u.net/economics/revision-notes/a2-macro-balance-of-payments-deficits.html
and the rest from ms sarah ee
here are my summarised points
BOP deficit will:
1:greatly reduce the investment and consumption confidence due to poor economic outlook, and if the country decides to increase interest rates to persuade the investors to keep investing in the economy, it'll have a negative effect on domestic investment and consumption.
2:make future growth difficult as their earnings would have to be used to repay the money borrowed previously.
3:cause a fall in employment as there is excessive foreign product consumption which results in a fall in domestic products demand and will hence result in a fall in domestic output and hence employment
4:cause the borrowing country to be influenced strongly by the lending country, both politically and economically
5:cause a downward pressure on exchange rates as there is a large supply of the currency in the foreign exchange market which may lead to imported inflation due to relatively more expensive imports, and may lead to a rise in interest rates in order to curb the inflation. while declining currency will reduce the relative price of exports and hence increase value of exports, there would be negative effect on demand, output and employment.
i hope these points will help you in your studies of BOP, because the consequence of BOP deficit is often solely "the country will be in debt", with no explanation. you can tag if you find this post useful in your studies.
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