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What do we mean by the following in organic chemistry?

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Original post by Stefan1991
Fair enough, but what is the difference?


eh? Biology and organic chemistry are totally different subjects! :facepalm:

biology is the study of living things and organic chemistry is the study of carbon compunds!!
Reply 21
Original post by Plato's Trousers
eh? Biology and organic chemistry are totally different subjects! :facepalm:

biology is the study of living things and organic chemistry is the study of carbon compunds!!


But all life on Earth is made out of carbon compounds...

I've only done biology and chemistry until GCSE and even I know that.
Reply 22
Original post by Stefan1991
But all life on Earth is made out of carbon compounds...

I've only done biology and chemistry until GCSE and even I know that.


yeah but the fact that you know that still does not justify biology is the same as organic chemistry.

i can say physical chemistry involves a lot of math, but why don't they just call it math? see the point. science can be multi-disciplinary. the truth is that organic chemistry may to a large extent involves biochemistry but also biophysics or materials, etc, you name it.
Original post by Stefan1991
But all life on Earth is made out of carbon compounds...

I've only done biology and chemistry until GCSE and even I know that.


That is a completely bogus argument!

Try explaining animal behaviour (which is part of biology) in terms of carbon chemistry. Or conversely, try explaining nucelophillic substitution using biology.
Reply 24
Original post by shengoc
yeah but the fact that you know that still does not justify biology is the same as organic chemistry.

i can say physical chemistry involves a lot of math, but why don't they just call it math? see the point. science can be multi-disciplinary. the truth is that organic chemistry may to a large extent involves biochemistry but also biophysics or materials, etc, you name it.


So it is biochemistry? That's what I actually meant rather than biology. Thanks.

And also does that not make it a subdivision of biology?

Original post by Plato's Trousers
That is a completely bogus argument!

Try explaining animal behaviour (which is part of biology) in terms of carbon chemistry. Or conversely, try explaining nucelophillic substitution using biology.


Is that not psychology? A type of biology...

I'm not sure what nucelophillic substitution is, as I said I've only done GCSE science.
I'm guessing it's something substituting something that likes nuclei? Nuclei that you'd find in organic animal cells? Doesn't that make it biology?
Reply 25
Original post by Stefan1991
So it is biochemistry? That's what I actually meant rather than biology. Thanks.

And also does that not make it a subdivision of biology?



Is that not psychology? A type of biology...

I'm not sure what nucelophillic substitution is, as I said I've only done GCSE science.
I'm guessing it's something substituting something that likes nuclei? Nuclei that you'd find in organic animal cells? Doesn't that make it biology?


it is called nucleophilic substitution, substitution of a nucleophile(nucleus-loving, atomic structure, hence chemistry/physics) with another nucleophile.

again psychology can be regarded as under life sciences or medical division really.
Sheesh! What a mess of attempts of explaining! Former teacher of chemistry here.

Organic chemistry definition:
It was believed a few hundred years ago ago that certain chemicals that contained carbon had a 'life force' that came from the living things they had come from. So chemistry was split into 2 fields: organic chemistry which looked at these chemicals that had a 'life force', and inorganic chemistry which looked at the other chemicals. As not all carbon containing chemicals appeared to have come from living things, not all carbon containing compounds were seen as 'organic' and therefore must be inorganic. For a long time these were seen as 2 completely different branches until a series of experiments by Wohler showed that chemicals that are 'organic' can be formed from reactions of purely 'inorganic' chemicals. Even so, the name has stuck (and there's a lot of rivalry between organic & inorganic chemists!)
Biology is the study of living organisms and their habitats. Biochemisty is the study of the roles of chemicals in living systems. Organic chemistry is the study of chemicals primarily consisting of Carbon and Hydrogen, although there may be a fair overlap between the latter two.

Homologous series:
A group of compounds that have
- the same general formula (CnH2n+2 etc etc)
- similar structural formulae,
- show similar chemical properties,
- and show a trend in physical properties (rising melting + boiling pts, decreasing flammability, increasing viscosity etc)

Saturated:
The word in all its meanings means 'full', eg a saturated towel is so full of water it can't hold any more, or a saturated salt solution can't dissolve any more sugar.
When it comes to hydrocarbons, it means 'full of hydrogen'. An alkane is 'full of hydrogen' as there are no more positions for a hydrogen to be placed, ie all carbons are already making 4 single bonds. (For saturation, it is purely the C-C bonds that are looked at. Any C=O or similar present is ignored) If a hydrocarbon is 'unsaturated' it means it isn't 'full of hydrogen', ie more hydrogen atoms could be added. Google an image of ethene and ethane to see the difference for those unsure. Ethane has no more positions to place a hydrogen (ie saturated). Ethene has a double bond, which, if broken, would allow another pair of hydrogen atoms to be placed; one hydrogen added to each carbon. The same is true of ethyne which is H-C=C-H where the '=' sign here should have 3 lines, ie a triple bond. It too can have more hydrogen added, and is therefore 'unsaturated'.

So, to summarise:
- Organic: chemicals containing mainly C and H, found primarily in living things (or their breakdown products: crude oil and coal, for example)
- Saturated: an organic chemical where all carbon to carbon bonds are _single_ bonds (the compound is 'full')
- Unsaturated: an organic compound that contains at least one carbon-to-carbon multiple bond. It may be any number of double or triple bonds. This compound is not 'full' of Hydrogen

For the person who mentioned 'methylene', it's probably not the best thing to mention, as for that matter you would have been just as well pointing out to the person that made the point about single bond hydrogen that Hydrogen is capable of more than one bond (in B2H6, 2 of the hydrogens are making 2 bonds each and are quite happy to do so) so even though interesting things exist, mentioning them is not always the best idea. It more often than not serves to confuse people.

I hope that this has helped.
(edited 13 years ago)
Reply 27
Original post by yaschaeffer
Sheesh! What a mess of attempts of explaining! Former teacher of chemistry here.

Organic chemistry definition:
It was believed a few hundred years ago ago that certain chemicals that contained carbon had a 'life force' that came from the living things they had come from. So chemistry was split into 2 fields: organic chemistry which looked at these chemicals that had a 'life force', and inorganic chemistry which looked at the other chemicals. As not all carbon containing chemicals appeared to have come from living things, not all carbon containing compounds were seen as 'organic' and therefore must be inorganic. For a long time these were seen as 2 completely different branches until a series of experiments by Wohler showed that chemicals that are 'organic' can be formed from reactions of purely 'inorganic' chemicals. Even so, the name has stuck (and there's a lot of rivalry between organic & inorganic chemists!)
Biology is the study of living organisms and their habitats. Biochemisty is the study of the roles of chemicals in living systems. Organic chemistry is the study of chemicals primarily consisting of Carbon and Hydrogen, although there may be a fair overlap between the latter two.

Homologous series:
A group of compounds that have
- the same general formula (CnH2n+2 etc etc)
- similar structural formulae,
- show similar chemical properties,
- and show a trend in physical properties (rising melting + boiling pts, decreasing flammability, increasing viscosity etc)

Saturated:
The word in all its meanings means 'full', eg a saturated towel is so full of water it can't hold any more, or a saturated salt solution can't dissolve any more sugar.
When it comes to hydrocarbons, it means 'full of hydrogen'. An alkane is 'full of hydrogen' as there are no more positions for a hydrogen to be placed, ie all carbons are already making 4 single bonds. (For saturation, it is purely the C-C bonds that are looked at. Any C=O or similar present is ignored) If a hydrocarbon is 'unsaturated' it means it isn't 'full of hydrogen', ie more hydrogen atoms could be added. Google an image of ethene and ethane to see the difference for those unsure. Ethane has no more positions to place a hydrogen (ie saturated). Ethene has a double bond, which, if broken, would allow another pair of hydrogen atoms to be placed; one hydrogen added to each carbon. The same is true of ethyne which is H-C=C-H where the '=' sign here should have 3 lines, ie a triple bond. It too can have more hydrogen added, and is therefore 'unsaturated'.

So, to summarise:
- Organic: chemicals containing mainly C and H, found primarily in living things (or their breakdown products: crude oil and coal, for example)
- Saturated: an organic chemical where all carbon to carbon bonds are _single_ bonds (the compound is 'full')
- Unsaturated: an organic compound that contains at least one carbon-to-carbon multiple bond. It may be any number of double or triple bonds. This compound is not 'full' of Hydrogen

For the person who mentioned 'methylene', it's probably not the best thing to mention, as for that matter you would have been just as well pointing out to the person that made the point about single bond hydrogen that Hydrogen is capable of more than one bond (in B2H6, 2 of the hydrogens are making 2 bonds each and are quite happy to do so) so even though interesting things exist, mentioning them is not always the best idea. It more often than not serves to confuse people.

I hope that this has helped.


well molecular orbital is an approximation in reality. though it depicts real situations very closely. in B2H6, I believe it is a three centre 2 H bond so the H are not exactly having two bonds. it is just the case of representing them that way. ie sometimes depiction of RO-Na is seen though it should really have been RO- Na+

I disagree with pointing out interesting facts. the thing about school syllabuses nowadays is that students tend not to be aware of interesting issues. and it is now and then people at this forum point out these interesting stuff, then they might become interested and inquire more, why? how? etc....curiosity is what drives science forwards. though it seems school is all about exams nowadays
Original post by shengoc
well molecular orbital is an approximation in reality. though it depicts real situations very closely. in B2H6, I believe it is a three centre 2 H bond so the H are not exactly having two bonds. it is just the case of representing them that way. ie sometimes depiction of RO-Na is seen though it should really have been RO- Na+

I disagree with pointing out interesting facts. the thing about school syllabuses nowadays is that students tend not to be aware of interesting issues. and it is now and then people at this forum point out these interesting stuff, then they might become interested and inquire more, why? how? etc....curiosity is what drives science forwards. though it seems school is all about exams nowadays


Ahaa!! Trap baited, set and sprung! Good to see that someone here actually pointed out my deliberate simplification. B2H6 and I go waaay back: I had uni exams where for that whole week I had a _really_ bad (walking dead almost) flu, and had decided to sit my exams 'on the off-chance' rather than stay in bed and have to resit everything. I ended up sitting under a hot air vent for the exam (typical!), and passed out (totally unnoticed by the invigilators I may add!) during it! The only part of the exam I remember is the 1st question: Describe the bonding in B2H6. 30 marks or so. Don't ask me how, but I passed that exam!
Yeah, I agree with you, exams exams exams.... there is no time for things that appear 'unusual'. The thing most people don't realise is that scientific discovery almost never starts with 'Eureka'. It usually starts with someone saying 'Huh? That's funny.' Good discovery comes hand in hand with blind luck and tenacity in the face of adversity (look up the Mpemba Effect for example)
As regards pointing out the interesting I agree with you, they should be pointed out. However, it should be toned down a little when someone is trying to understand the basics: there is a world between understanding methane and methylene to use the previous example... especially when they are having difficulty with the basics. I threw in the diborane example to show that 'things are not always as they appear to be'. My high school physics teacher used to say something about physics, which is true of all sciences: 'Physics is a series of diminishing lies'. ie in chemistry you learn about 'substances' then you learn about 'atoms' and 'molecules', then concentric circles with overlaps, then petal diagrams, 3D orbitals, then electron densities, then probabilities and solving schroedinger's (not much fun, let me tell you!!), etc etc etc and at each step, you find out that each step beforehand was just a simplification of the 'real thing' ie 'you've been lied to'. So people studying science should always remember that it's all just a simplification... it's just that the 'lies' get fewer and fewer as you get further advanced and there will always be something out there that makes you think 'Wait a minute! That can't be right!?'
Food for thought.
Original post by Stefan1991
So it is biochemistry? That's what I actually meant rather than biology. Thanks.

And also does that not make it a subdivision of biology?



Is that not psychology? A type of biology...

I'm not sure what nucelophillic substitution is, as I said I've only done GCSE science.
I'm guessing it's something substituting something that likes nuclei? Nuclei that you'd find in organic animal cells? Doesn't that make it biology?


you are very confused about all this. I hope this will clarify

biochemistry is the study of the chemistry of living systems. It is mostly made up of organic chemistry, but also contains lots of physical and inorganic chemistry. It is therefore not the same as organic chemistry.

organic chemistry is the study of the chemistry of carbon containing compounds. How is this anything like biology? There are vast areas of carbon chemistry (organic chemistry) that have nothing to do with biology at all.

biology is not chemistry at all (though it may make use of biochemistry to explain a number of ideas. It is the study of all aspects of living things; their reproduction, metabolism, behaviour, genetics, taxonomy etc.

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