Can someone explain this statement on functional groups/ organic chemistry

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Angel_Chen
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I've literally copied this from the AQA GCSE Chemistry spec: It is the generality of reactions of functional groups that determine the reactions of organic compounds.
Can someone explain what this actually means?
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_NMcC_
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I think this is very relatable to maths actually.

Say you have an equation, Y = a^2 + ✓b - Sin(x).

Where x = 20

You don't know much about the other terms but you know that the Sine will always produce a ratio of lengths for a certain angle (x) - opposite/hypotenuse.

The same idea or line of thinking can be applied to Organic Chemistry.

A functional group is a group of atoms that will react predictability with other specific functional groups under certain conditions e.g Reflux, 120 degrees C

A simple example is the Fischer esterification of primary Alcohols with Carboxylic Acids under reflux. This reaction will always produce esters, regardless (usually) of what else is on the molecule.

There is however naturally less rigour in Organic Chemistry than more 'pure' subjects like Physics. Simply because Chemistry leans more on the side of empirical science rather than the Theoretical - reliant more on experimental evidence than theory. There are often more subtle variables at play as well that determine reactivity including Leaving group ability, electronegativity, geometry and acidity.

Nevertheless, this line of thinking is ultimately how molecules like vitamin B12 came to be synthesized and many anti-cancer drugs. Retro synthetic analysis is essentially chopping up a desired molecule into known functional groups and their corresponding reactions. Going backwards.

Physics has yet to come up with a better methodology for synthesizing complex molecules.
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Angel_Chen
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(Original post by _NMcC_)
I think this is very relatable to maths actually.

Say you have an equation, Y = a^2 + ✓b - Sin(x).

Where x = 20

You don't know much about the other terms but you know that the Sine will always produce a ratio of lengths for a certain angle (x) - opposite/hypotenuse.

The same idea or line of thinking can be applied to Organic Chemistry.

A functional group is a group of atoms that will react predictability with other specific functional groups under certain conditions e.g Reflux, 120 degrees C

A simple example is the Fischer esterification of primary Alcohols with Carboxylic Acids under reflux. This reaction will always produce esters, regardless (usually) of what else is on the molecule.

There is however naturally less rigour in Organic Chemistry than more 'pure' subjects like Physics. Simply because Chemistry leans more on the side of empirical science rather than the Theoretical - reliant more on experimental evidence than theory. There are often more subtle variables at play as well that determine reactivity including Leaving group ability, electronegativity, geometry and acidity.

Nevertheless, this line of thinking is ultimately how molecules like vitamin B12 came to be synthesized and many anti-cancer drugs. Retro synthetic analysis is essentially chopping up a desired molecule into known functional groups and their corresponding reactions. Going backwards.

Physics has yet to come up with a better methodology for synthesizing complex molecules.
This is a really long and detailed explanation, so thank you but I have no idea about what half of the stuff you are talking about. Is it basically all the functional groups reactions are the ones visible/always happen when molecules containing these atoms react, no matter what else is present?
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themedicalone
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(Original post by Angel_Chen)
I've literally copied this from the AQA GCSE Chemistry spec: It is the generality of reactions of functional groups that determine the reactions of organic compounds.
Can someone explain what this actually means?
Basically, organic compounds have different functional groups, like -OH or -COOH. and depending on the functional group is how that set of organic compounds reacts.
So all alcohols react in a similar way, all Carboxylic acids react in a similar way etc.
so dissecting the definition: each function group has its own unique set of characteristics, and react in a unique way, so any other compounds with that specific functional group will react in the same way
Hope this made some sense
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Angel_Chen
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(Original post by themedicalone)
Basically, organic compounds have different functional groups, like -OH or -COOH. and depending on the functional group is how that set of organic compounds reacts.
So all alcohols react in a similar way, all Carboxylic acids react in a similar way etc.
so dissecting the definition: each function group has its own unique set of characteristics, and react in a unique way, so any other compounds with that specific functional group will react in the same way
Hope this made some sense
Thank you so much, I really hate how complictated and wordy specifications make explanations sometimes.
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themedicalone
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(Original post by Angel_Chen)
Thank you so much, I really hate how complictated and wordy specifications make explanations sometimes.
No worries! and i know tell me about it haha, good luck with your exam
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Angel_Chen
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(Original post by themedicalone)
No worries! and i know tell me about it haha, good luck with your exam
Thanx! Have a good day!
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_NMcC_
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(Original post by Angel_Chen)
This is a really long and detailed explanation, so thank you but I have no idea about what half of the stuff you are talking about. Is it basically all the functional groups reactions are the ones visible/always happen when molecules containing these atoms react, no matter what else is present?
Yes so a functional group is a designated set of atoms in a molecule that will determine the overall reactivity of the molecule.

Under-standard conditions, C-H and C-C bonds won't react. They are normally referred to by Chemists as 'R' groups and are the parts of the molecule that can be ignored with confidence.

In most cases. Anything with Oxygen, Nitrogen or one of the Halogens is likely to be a known functional group. Alkenes and Alkynes are also considered as functional groups along with some Sulphur and Phosphorus groups.

Metals are used as reagents and aren't considered 'functional' in an Organic sense and metalloids are very unusual.

So with functional groups, you definitely in the non-metals area of the periodic table.

Eventually, with practice you will become intuitively aware of the most common functional groups like Alcohols or Ketones and less common ones like Carbenes or Diazenes.
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