Organic chemistry might seem overwhelming at first, but it's actually...
Chemistry331 views·Updated 17 Sept 2026·3 pagesUnderstanding AQA AS Organic Chemistry: Basics and Key Topics
B
bv@bv
1 / 3
1
of 3
Introduction to Organic Chemistry and Naming Rules
Understanding molecular formulae is your first step into organic chemistry. You'll encounter different types: empirical (simplest ratio), molecular (actual numbers of atoms), structural (showing connections), displayed (every bond drawn), and skeletal (simplified diagrams). Think of these as different ways to describe the same molecule - like giving directions using a map versus landmarks.
Homologous series are families of compounds that share the same functional group - the bit that makes them react in similar ways. Each series has its own general formula, making it dead easy to work out molecular formulae once you know the pattern.
The IUPAC naming system follows simple rules that work like a code. Start with the stem (meth-, eth-, prop-, but-, pent-) based on carbon count, then add the ending based on the functional group (-ol for alcohols, -one for ketones, -al for aldehydes, -oic acid for carboxylic acids).
Quick Tip: Always find the longest carbon chain that includes the functional group - that's your main stem. Number carbons to give the functional group the lowest possible number.
2
of 3
Isomerism - Same Formula, Different Arrangements
Structural isomers have identical molecular formulae but completely different atom arrangements. You'll spot three types: chain isomers (straight vs branched), position isomers (functional group in different spots), and functional group isomers (different functional groups entirely). It's like having the same Lego pieces but building different models.
Stereoisomers are trickier - same formula and functional groups, but atoms arranged differently in 3D space. This happens around double bonds because they can't rotate freely like single bonds.
E/Z isomerism occurs at double bonds where you compare the positions of the largest groups. Z means the big groups are on the "zame zide" (same side), while E means they're on opposite sides. For complex molecules, use CIP rules - rank the four atoms directly attached to the double bond by atomic mass, then see if the top two priorities are together (Z) or apart (E).
Memory Trick: "Z = Zame Zide" - the two highest priority groups are on the same side of the double bond.
3
of 3
Reaction Mechanisms and Free Radicals
Reaction mechanisms show exactly how bonds break and form during chemical reactions. They're like step-by-step instructions for molecular transformations, helping you predict what happens when molecules collide.
Curly arrows are your best mates for showing electron movement. These arrows always show where electron pairs go - either forming new bonds or breaking existing ones. Master these, and you'll understand why reactions happen the way they do.
Free radicals are highly reactive molecules with unpaired electrons, shown with a dot. They're incredibly unstable and will react with almost anything to pair up that lonely electron. Think of them as molecular desperados looking for a partner.
Key Point: Curly arrows always show electron pair movement - never just point randomly between atoms. Follow the electrons, and you'll follow the reaction.
We thought you’d never ask...
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.
Similar content
Most popular content: Functional Groups
5ChemistryOrganic reactions unit 2
Functional groups conversions
1270
ChemistryFunctional Group Overview
Explore the key functional groups in organic chemistry, including alkenes, ketones, carboxylic acids, alcohols, and aldehydes. This summary highlights their structures, properties, and significance in chemical compounds. Ideal for students studying organic chemistry concepts.
12440
ChemistryIdentifying Organic Functional Groups
Explore the methods for identifying functional groups in organic compounds, including reactions with bromine water, silver nitrate, and 2,4-DNP. This summary covers key observations and techniques such as recrystallization and melting point comparison, essential for A Level chemistry students.
12250
ChemistryFunctional Groups Identification
Explore the identification of functional groups including aldehydes, carboxylic acids, and alcohols through various reagents like Tollens' reagent and acidified potassium dichromate. This summary highlights key observations such as the formation of a silver mirror and color changes in solutions, essential for A-level chemistry students.
12100
ChemistryNATIONAL 5 Chemistry - UNIT 2
Completed Unit 2 notes for national 5 chemistry
S4510
Most popular content in Chemistry
9ChemistryChemisty Paper 1 Summary
Everything you need to know condensed into three pages
112,53557
ChemistryA-level OCR A Chemistry summary sheets
Everything from snaprevise for OCR chemistry a-level
122,52289
Chemistrychem paper 1
higher
112,33047
ChemistryRedox Reactions Overview
Explore the fundamentals of redox reactions, including oxidation states, definitions of oxidation and reduction, and the roles of oxidizing and reducing agents. This summary covers key rules for determining oxidation states, the concept of disproportionation, and practical applications in chemical equations. Ideal for A-Level Chemistry students preparing for exams.
126,461323
ChemistryBTEC Applied Science Unit 1 Overview
Comprehensive resource for Year 12 students pursuing a Level 3 Diploma in Applied Science. This booklet covers essential topics including cell structure, chemical properties, and wave theory, providing clear explanations and key concepts to aid in your studies and exam preparation.
125,622129
ChemistryAlevel Chemistry
Alevel Chemistry AQA
122828
ChemistryIGCSE Chemistry Concepts
Explore essential IGCSE Chemistry concepts including states of matter, chemical bonding, acid-base reactions, and separation methods. This comprehensive summary covers key topics such as ionic and covalent bonds, solubility rules, and the periodic table, tailored for Edexcel IGCSE Double Award students. Perfect for exam preparation and understanding fundamental chemistry principles.
111,46345
BiologyComprehensive GCSE Science Overview
Explore a detailed compilation of key concepts across Biology, Chemistry, and Physics for the GCSE curriculum. This resource covers essential topics, including atomic structure, ecosystems, chemical reactions, and more, providing students with a thorough understanding to excel in their studies. Ideal for revision and exam preparation.
115,277644
ChemistryOCR A-Level Chemistry Vocabulary
Explore an extensive collection of key terms and concepts for OCR A-Level Chemistry, organized by topic and sub-topic. This resource is designed to enhance your understanding and application of advanced vocabulary in exams, covering essential areas such as atomic structure, organic chemistry, and reaction mechanisms.
122458
Most popular content
9
SociologySociology of Families: Comprehensive Revision
Dive into an extensive overview of family dynamics, perspectives, and patterns in sociology. This resource covers key concepts such as family diversity, gender roles, marriage, and the impact of social policies on family structures. Perfect for A-Level Sociology students preparing for Paper 2.
1274,2332,307
SociologySociology of Education Overview
Explore comprehensive A-Level Sociology notes on the education system, covering key theories, policies, and sociological perspectives. This resource includes insights on marketisation, gender roles, cultural deprivation, and educational inequalities, providing a thorough understanding of how education shapes social stratification and individual achievement. Ideal for exam preparation and in-depth study.
12103,3913,046
BiologyAQA Biology: Key Concepts
Explore essential AQA Biology topics including Photosynthesis, Respiration, Homeostasis, Genetics, and Ecology. This comprehensive knowledge organizer covers key concepts such as energy transfer, hormonal control, and genetic variation, providing a solid foundation for your studies. Ideal for exam preparation and understanding biological processes.
109,307316
BiologyA-Level Biology Year 1 Overview
Comprehensive summary of AQA A-Level Biology Year 1, covering key topics such as cellular structure, protein synthesis, immune response, gas exchange, and more. Ideal for exam preparation and understanding biological concepts. Includes detailed insights into cellular processes, biological classification, and the circulatory system.
1215,286704
MathsComprehensive Maths Concepts
Explore essential mathematical concepts including powers, geometry, statistics, and probability. This resource features 65 pages of detailed explanations, diagrams, and examples to enhance your understanding of topics such as right triangles, volume calculations, and data representation. Ideal for students seeking to strengthen their numeracy skills and grasp complex mathematical principles.
1180,4266,328
SociologyComprehensive Crime & Deviance Overview
Explore an extensive revision of crime and deviance topics, including theories, types of crime, and the impact of media. This resource covers key concepts such as Marxism, functionalism, gender and crime, and the influence of globalization on criminal behavior. Ideal for students seeking a thorough understanding of criminology and its various theories. Type: Full Topic Revision.
1251,9811,410
CriminologyCriminal Justice Overview
Explore key concepts in criminal justice, including the trial process, roles of court personnel, types of offenses, and evidence handling. This comprehensive summary covers essential topics such as jury strengths and weaknesses, the role of the CPS, and the impact of media on trials. Ideal for students preparing for assessments in criminology. Achieved a B grade.
133,54674
CriminologyCriminal Justice Evidence Rules
Explore the essential rules governing the use of evidence in criminal cases, including reliability, admissibility, and relevance. This summary covers key concepts such as the roles of personnel in investigations, the impact of witness testimonies, and the implications of plea bargaining. Ideal for Year 13 criminology students preparing for assessments.
1211,225179
SociologySociological Theories Overview
Comprehensive revision of key sociological theories including Functionalism, Marxism, Feminism, and Interpretivism. Explore concepts like value freedom, identity formation, and the critique of social control. Ideal for AQA A-Level Sociology students preparing for exams. This summary covers essential theories and their implications in sociology, providing a clear understanding of each perspective.
1231,850851
Students love us, and so will you.
4.6/5App Store
4.7/5Google 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 SiOS 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 KlichAndroid 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.
AnnaiOS user
Chemistry331 views·Updated 17 Sept 2026·3 pagesUnderstanding AQA AS Organic Chemistry: Basics and Key Topics
B
bv@bv
Organic chemistry might seem overwhelming at first, but it's actually just about learning how to name molecules and understand how they behave. Once you get the hang of the naming rules and can spot different types of isomers, you'll find...
1
of 3
Sign up to see the content. It's free!
- Access to all documents
- Improve your grades
- Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Introduction to Organic Chemistry and Naming Rules
Understanding molecular formulae is your first step into organic chemistry. You'll encounter different types: empirical (simplest ratio), molecular (actual numbers of atoms), structural (showing connections), displayed (every bond drawn), and skeletal (simplified diagrams). Think of these as different ways to describe the same molecule - like giving directions using a map versus landmarks.
Homologous series are families of compounds that share the same functional group - the bit that makes them react in similar ways. Each series has its own general formula, making it dead easy to work out molecular formulae once you know the pattern.
The IUPAC naming system follows simple rules that work like a code. Start with the stem (meth-, eth-, prop-, but-, pent-) based on carbon count, then add the ending based on the functional group (-ol for alcohols, -one for ketones, -al for aldehydes, -oic acid for carboxylic acids).
Quick Tip: Always find the longest carbon chain that includes the functional group - that's your main stem. Number carbons to give the functional group the lowest possible number.
2
of 3Sign up to see the content. It's free!
- Access to all documents
- Improve your grades
- Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Isomerism - Same Formula, Different Arrangements
Structural isomers have identical molecular formulae but completely different atom arrangements. You'll spot three types: chain isomers (straight vs branched), position isomers (functional group in different spots), and functional group isomers (different functional groups entirely). It's like having the same Lego pieces but building different models.
Stereoisomers are trickier - same formula and functional groups, but atoms arranged differently in 3D space. This happens around double bonds because they can't rotate freely like single bonds.
E/Z isomerism occurs at double bonds where you compare the positions of the largest groups. Z means the big groups are on the "zame zide" (same side), while E means they're on opposite sides. For complex molecules, use CIP rules - rank the four atoms directly attached to the double bond by atomic mass, then see if the top two priorities are together (Z) or apart (E).
Memory Trick: "Z = Zame Zide" - the two highest priority groups are on the same side of the double bond.
3
of 3Sign up to see the content. It's free!
- Access to all documents
- Improve your grades
- Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Reaction Mechanisms and Free Radicals
Reaction mechanisms show exactly how bonds break and form during chemical reactions. They're like step-by-step instructions for molecular transformations, helping you predict what happens when molecules collide.
Curly arrows are your best mates for showing electron movement. These arrows always show where electron pairs go - either forming new bonds or breaking existing ones. Master these, and you'll understand why reactions happen the way they do.
Free radicals are highly reactive molecules with unpaired electrons, shown with a dot. They're incredibly unstable and will react with almost anything to pair up that lonely electron. Think of them as molecular desperados looking for a partner.
Key Point: Curly arrows always show electron pair movement - never just point randomly between atoms. Follow the electrons, and you'll follow the reaction.
We thought you’d never ask...
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.
Similar content
Most popular content: Functional Groups
5ChemistryOrganic reactions unit 2
Functional groups conversions
1270
ChemistryFunctional Group Overview
Explore the key functional groups in organic chemistry, including alkenes, ketones, carboxylic acids, alcohols, and aldehydes. This summary highlights their structures, properties, and significance in chemical compounds. Ideal for students studying organic chemistry concepts.
12440
ChemistryIdentifying Organic Functional Groups
Explore the methods for identifying functional groups in organic compounds, including reactions with bromine water, silver nitrate, and 2,4-DNP. This summary covers key observations and techniques such as recrystallization and melting point comparison, essential for A Level chemistry students.
12250
ChemistryFunctional Groups Identification
Explore the identification of functional groups including aldehydes, carboxylic acids, and alcohols through various reagents like Tollens' reagent and acidified potassium dichromate. This summary highlights key observations such as the formation of a silver mirror and color changes in solutions, essential for A-level chemistry students.
12100
ChemistryNATIONAL 5 Chemistry - UNIT 2
Completed Unit 2 notes for national 5 chemistry
S4510
Most popular content in Chemistry
9ChemistryChemisty Paper 1 Summary
Everything you need to know condensed into three pages
112,53557
ChemistryA-level OCR A Chemistry summary sheets
Everything from snaprevise for OCR chemistry a-level
122,52289
Chemistrychem paper 1
higher
112,33047
ChemistryRedox Reactions Overview
Explore the fundamentals of redox reactions, including oxidation states, definitions of oxidation and reduction, and the roles of oxidizing and reducing agents. This summary covers key rules for determining oxidation states, the concept of disproportionation, and practical applications in chemical equations. Ideal for A-Level Chemistry students preparing for exams.
126,461323
ChemistryBTEC Applied Science Unit 1 Overview
Comprehensive resource for Year 12 students pursuing a Level 3 Diploma in Applied Science. This booklet covers essential topics including cell structure, chemical properties, and wave theory, providing clear explanations and key concepts to aid in your studies and exam preparation.
125,622129
ChemistryAlevel Chemistry
Alevel Chemistry AQA
122828
ChemistryIGCSE Chemistry Concepts
Explore essential IGCSE Chemistry concepts including states of matter, chemical bonding, acid-base reactions, and separation methods. This comprehensive summary covers key topics such as ionic and covalent bonds, solubility rules, and the periodic table, tailored for Edexcel IGCSE Double Award students. Perfect for exam preparation and understanding fundamental chemistry principles.
111,46345
BiologyComprehensive GCSE Science Overview
Explore a detailed compilation of key concepts across Biology, Chemistry, and Physics for the GCSE curriculum. This resource covers essential topics, including atomic structure, ecosystems, chemical reactions, and more, providing students with a thorough understanding to excel in their studies. Ideal for revision and exam preparation.
115,277644
ChemistryOCR A-Level Chemistry Vocabulary
Explore an extensive collection of key terms and concepts for OCR A-Level Chemistry, organized by topic and sub-topic. This resource is designed to enhance your understanding and application of advanced vocabulary in exams, covering essential areas such as atomic structure, organic chemistry, and reaction mechanisms.
122458
Most popular content
9SociologySociology of Families: Comprehensive Revision
Dive into an extensive overview of family dynamics, perspectives, and patterns in sociology. This resource covers key concepts such as family diversity, gender roles, marriage, and the impact of social policies on family structures. Perfect for A-Level Sociology students preparing for Paper 2.
1274,2332,307
SociologySociology of Education Overview
Explore comprehensive A-Level Sociology notes on the education system, covering key theories, policies, and sociological perspectives. This resource includes insights on marketisation, gender roles, cultural deprivation, and educational inequalities, providing a thorough understanding of how education shapes social stratification and individual achievement. Ideal for exam preparation and in-depth study.
12103,3913,046
BiologyAQA Biology: Key Concepts
Explore essential AQA Biology topics including Photosynthesis, Respiration, Homeostasis, Genetics, and Ecology. This comprehensive knowledge organizer covers key concepts such as energy transfer, hormonal control, and genetic variation, providing a solid foundation for your studies. Ideal for exam preparation and understanding biological processes.
109,307316
BiologyA-Level Biology Year 1 Overview
Comprehensive summary of AQA A-Level Biology Year 1, covering key topics such as cellular structure, protein synthesis, immune response, gas exchange, and more. Ideal for exam preparation and understanding biological concepts. Includes detailed insights into cellular processes, biological classification, and the circulatory system.
1215,286704
MathsComprehensive Maths Concepts
Explore essential mathematical concepts including powers, geometry, statistics, and probability. This resource features 65 pages of detailed explanations, diagrams, and examples to enhance your understanding of topics such as right triangles, volume calculations, and data representation. Ideal for students seeking to strengthen their numeracy skills and grasp complex mathematical principles.
1180,4266,328
SociologyComprehensive Crime & Deviance Overview
Explore an extensive revision of crime and deviance topics, including theories, types of crime, and the impact of media. This resource covers key concepts such as Marxism, functionalism, gender and crime, and the influence of globalization on criminal behavior. Ideal for students seeking a thorough understanding of criminology and its various theories. Type: Full Topic Revision.
1251,9811,410
CriminologyCriminal Justice Overview
Explore key concepts in criminal justice, including the trial process, roles of court personnel, types of offenses, and evidence handling. This comprehensive summary covers essential topics such as jury strengths and weaknesses, the role of the CPS, and the impact of media on trials. Ideal for students preparing for assessments in criminology. Achieved a B grade.
133,54674
CriminologyCriminal Justice Evidence Rules
Explore the essential rules governing the use of evidence in criminal cases, including reliability, admissibility, and relevance. This summary covers key concepts such as the roles of personnel in investigations, the impact of witness testimonies, and the implications of plea bargaining. Ideal for Year 13 criminology students preparing for assessments.
1211,225179
SociologySociological Theories Overview
Comprehensive revision of key sociological theories including Functionalism, Marxism, Feminism, and Interpretivism. Explore concepts like value freedom, identity formation, and the critique of social control. Ideal for AQA A-Level Sociology students preparing for exams. This summary covers essential theories and their implications in sociology, providing a clear understanding of each perspective.
1231,850851
Students love us, and so will you.
4.6/5App Store
4.7/5Google 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 SiOS 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 KlichAndroid 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.
AnnaiOS user