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Chemistry
30 Nov 2025
34
2 pages
Understanding organic chemistry is crucial for your A-levels, especially when it comes to fuels and how they work.... Show more
You'll need to master the different organic functional groups to succeed in chemistry. Alcohols contain the OH (hydroxyl) group with the formula CₙH₂ₙ₊₁OH, whilst haloalkanes have group 7 elements like chlorine or bromine attached. Ethers are simpler - they just have a single oxygen atom stuck in the middle of an alkane chain.
Learning the naming prefixes is absolutely essential for exams. The sequence "meth, eth, prop, but, pent, hex, hept, oct, non, dec" tells you how many carbon atoms are present (1 to 10 respectively). When you see multiple double bonds, add "diene" for two or "triene" for three.
Molecular shapes depend entirely on the bonding around carbon atoms. Single bonds create a tetrahedral shape (109.5°), whilst double bonds form a trigonal planar structure (120°). Remember that sigma bonds (direct overlap) are always stronger than pi bonds (sideways overlap).
Quick tip The "Monkeys Eat Peanut Butter" mnemonic helps you remember meth-eth-prop-but!
Isomerism might seem tricky, but it's just about molecules with the same atoms arranged differently. Structural isomers have different structural formulas, whilst stereoisomers have the same structural formula but different 3D arrangements. E/Z isomerism occurs because double bonds can't rotate freely.
Electrophilic addition reactions are key to understanding how alkenes behave. An electrophile is simply a positive ion that's attracted to negative regions and accepts electron pairs. When alkenes react with substances like bromine, they form carbocations (positively charged carbon ions) as intermediates.
Addition polymerisation transforms small molecules called monomers into huge polymer chains. Ethene monomers, for example, join together to create polyethene through this process. This reaction is vital for producing plastics and understanding how fuels can be converted into useful materials.
Modern fuel alternatives each have distinct advantages and drawbacks. Ethanol produces less harmful emissions but uses land that could grow food. Hydrogen only produces water when burned but is incredibly difficult to store safely. LPG (liquefied petroleum gas) creates fewer pollutants than petrol but requires special storage equipment.
Remember Complete combustion always produces CO₂ and H₂O, whilst incomplete combustion creates dangerous CO and carbon particles.
Combustion reactions follow predictable patterns. Alkanes, cycloalkanes, and alcohols all burn in oxygen to produce carbon dioxide and water. However, real-world combustion creates pollutants like sulfur dioxide (from sulfur impurities), nitrogen oxides , and carbon monoxide (from incomplete burning). Catalytic converters help reduce these harmful emissions.
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
You can download the app from Google Play Store and Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
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Explore essential synthetic routes for aliphatic compounds in organic chemistry. This summary covers reaction pathways for alkanes, alcohols, ketones, and carboxylic acids, detailing key reagents and conditions. Ideal for OCR A Level Chemistry students seeking to master organic synthesis mechanisms.
ChemistryExplore key concepts in organic chemistry, including functional groups, IUPAC nomenclature, reaction mechanisms, and polymer chemistry. This comprehensive summary covers aromatic compounds, alkenes, aldehydes, ketones, and mass spectrometry, providing essential insights for students. Ideal for exam preparation and understanding organic synthesis, chemical reactions, and molecular structures.
ChemistryExplore key concepts in organic chemistry, including reaction mechanisms, stereochemistry, and functional groups. This comprehensive summary covers alcohols, alkenes, carboxylic acids, and more, providing insights into molecular structures and properties. Ideal for IB Chemistry HL students preparing for exams.
ChemistryExplore the chemistry of alcohols and carboxylic acids, including their structures, properties, and reactions. This summary covers homologous series, energy calculations, and the fermentation process for ethanol production. Ideal for students studying organic chemistry.
ChemistryExplore the key concepts of aromatic chemistry, focusing on benzene's structure, stability, and reactions. This summary covers delocalization, electrophilic substitution mechanisms, and the significance of arenes in organic chemistry. Ideal for AQA A-Level students seeking a concise overview of aromatic compounds.
ChemistryExplore the processes of alcohol oxidation and saponification in this detailed summary. Learn how primary and secondary alcohols are oxidized using acidified dichromate and copper(II) oxide, and understand the formation of soaps through the hydrolysis of fats and oils. Key concepts include functional groups, reaction mechanisms, and the role of antioxidants. Ideal for chemistry students preparing for exams.
ChemistryApp Store
Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
Understanding organic chemistry is crucial for your A-levels, especially when it comes to fuels and how they work. This topic covers everything from the basic structure of organic molecules to how we're developing cleaner alternatives to petrol and diesel.
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You'll need to master the different organic functional groups to succeed in chemistry. Alcohols contain the OH (hydroxyl) group with the formula CₙH₂ₙ₊₁OH, whilst haloalkanes have group 7 elements like chlorine or bromine attached. Ethers are simpler - they just have a single oxygen atom stuck in the middle of an alkane chain.
Learning the naming prefixes is absolutely essential for exams. The sequence "meth, eth, prop, but, pent, hex, hept, oct, non, dec" tells you how many carbon atoms are present (1 to 10 respectively). When you see multiple double bonds, add "diene" for two or "triene" for three.
Molecular shapes depend entirely on the bonding around carbon atoms. Single bonds create a tetrahedral shape (109.5°), whilst double bonds form a trigonal planar structure (120°). Remember that sigma bonds (direct overlap) are always stronger than pi bonds (sideways overlap).
Quick tip: The "Monkeys Eat Peanut Butter" mnemonic helps you remember meth-eth-prop-but!
Isomerism might seem tricky, but it's just about molecules with the same atoms arranged differently. Structural isomers have different structural formulas, whilst stereoisomers have the same structural formula but different 3D arrangements. E/Z isomerism occurs because double bonds can't rotate freely.
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Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Electrophilic addition reactions are key to understanding how alkenes behave. An electrophile is simply a positive ion that's attracted to negative regions and accepts electron pairs. When alkenes react with substances like bromine, they form carbocations (positively charged carbon ions) as intermediates.
Addition polymerisation transforms small molecules called monomers into huge polymer chains. Ethene monomers, for example, join together to create polyethene through this process. This reaction is vital for producing plastics and understanding how fuels can be converted into useful materials.
Modern fuel alternatives each have distinct advantages and drawbacks. Ethanol produces less harmful emissions but uses land that could grow food. Hydrogen only produces water when burned but is incredibly difficult to store safely. LPG (liquefied petroleum gas) creates fewer pollutants than petrol but requires special storage equipment.
Remember: Complete combustion always produces CO₂ and H₂O, whilst incomplete combustion creates dangerous CO and carbon particles.
Combustion reactions follow predictable patterns. Alkanes, cycloalkanes, and alcohols all burn in oxygen to produce carbon dioxide and water. However, real-world combustion creates pollutants like sulfur dioxide (from sulfur impurities), nitrogen oxides , and carbon monoxide (from incomplete burning). Catalytic converters help reduce these harmful emissions.
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
You can download the app from Google Play Store and Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
2
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Explore essential synthetic routes for aliphatic compounds in organic chemistry. This summary covers reaction pathways for alkanes, alcohols, ketones, and carboxylic acids, detailing key reagents and conditions. Ideal for OCR A Level Chemistry students seeking to master organic synthesis mechanisms.
ChemistryExplore key concepts in organic chemistry, including functional groups, IUPAC nomenclature, reaction mechanisms, and polymer chemistry. This comprehensive summary covers aromatic compounds, alkenes, aldehydes, ketones, and mass spectrometry, providing essential insights for students. Ideal for exam preparation and understanding organic synthesis, chemical reactions, and molecular structures.
ChemistryExplore key concepts in organic chemistry, including reaction mechanisms, stereochemistry, and functional groups. This comprehensive summary covers alcohols, alkenes, carboxylic acids, and more, providing insights into molecular structures and properties. Ideal for IB Chemistry HL students preparing for exams.
ChemistryExplore the chemistry of alcohols and carboxylic acids, including their structures, properties, and reactions. This summary covers homologous series, energy calculations, and the fermentation process for ethanol production. Ideal for students studying organic chemistry.
ChemistryExplore the key concepts of aromatic chemistry, focusing on benzene's structure, stability, and reactions. This summary covers delocalization, electrophilic substitution mechanisms, and the significance of arenes in organic chemistry. Ideal for AQA A-Level students seeking a concise overview of aromatic compounds.
ChemistryExplore the processes of alcohol oxidation and saponification in this detailed summary. Learn how primary and secondary alcohols are oxidized using acidified dichromate and copper(II) oxide, and understand the formation of soaps through the hydrolysis of fats and oils. Key concepts include functional groups, reaction mechanisms, and the role of antioxidants. Ideal for chemistry students preparing for exams.
ChemistryApp Store
Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
Sociology