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Updated Mar 19, 2026
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Crude Oil Magic: How Fractional Distillation Turns Oil into Different Fuels
Tanaka Machiridza
@tanakamachiridza
1 / 6
Burning Hydrocarbons
Hydrocarbons serve as important fuels due to their ability to release useful energy when reacted with oxygen. This process is known as combustion.
Definition: A fuel is a substance that reacts with oxygen to release useful energy.
Complete combustion occurs when there is an abundance of oxygen. The products of complete combustion of any hydrocarbon in oxygen are carbon dioxide and water.
Example: The balanced symbol equation for the complete combustion of methane (CH₄) is: CH₄ + 2O₂ → CO₂ + 2H₂O + energy
Highlight: It's crucial to ensure that the number of carbon, hydrogen, and oxygen atoms are the same on both sides of the equation.
Vocabulary: Volatile hydrocarbons are those that evaporate readily, posing a significant fire risk. This is why smoking is prohibited at petrol stations.
Demonstrating Combustion Products
To demonstrate that a hydrocarbon fuel burns to produce carbon dioxide and water, a specific experimental setup can be used. This setup involves burning hexane and collecting the combustion products.
- A water pump draws gases from the burning hexane through the apparatus.
- Water collects inside a cooled U-tube, which can be identified by checking its boiling point.
- Limewater turns milky when carbon dioxide passes through it, indicating the presence of CO₂.
Example: In this experiment, hexane is used as the hydrocarbon fuel. The combustion products are passed through crushed ice and water to cool them, allowing water vapor to condense in the U-tube.
Highlight: This practical demonstration provides visual evidence of the products formed during the complete combustion of hydrocarbons.
Alkanes: Saturated Hydrocarbons
Alkanes are an important class of hydrocarbons found in crude oil. They have distinct properties based on their structure.
Definition: Alkanes are hydrocarbons made up of chains of carbon atoms joined by single covalent bonds, surrounded by hydrogen atoms.
Key characteristics of alkanes:
- They have the general formula CnH₂n+₂
- All carbon-carbon bonds are single bonds
- They are called saturated hydrocarbons because they have no spare bonds
Example: Methane (CH₄) and ethane (C₂H₆) are examples of alkanes.
Highlight: The difference between alkanes and alkenes can be determined by adding the substance to bromine water. Alkanes won't decolorize the bromine water as they have no spare bonds to react with bromine.
Vocabulary: Saturated hydrocarbons are compounds in which all carbon atoms are joined by single bonds, leaving no room for additional atoms to be added without breaking existing bonds.
Alkenes: Unsaturated Hydrocarbons
Alkenes are another important class of hydrocarbons found in crude oil. They differ from alkanes in their structure and properties.
Definition: Alkenes are hydrocarbons with chains of carbon atoms containing one or more double covalent bonds.
Key characteristics of alkenes:
- They have the general formula CnH₂n for those containing one double bond
- They are more reactive than alkanes due to their double bond
- They can form polymers by opening their double bonds
- They are called unsaturated hydrocarbons as their double bonds can open up and allow other atoms to join
Example: The first three alkenes are ethene (C₂H₄), propene (C₃H₆), and butene (C₄H₈).
Highlight: The difference between alkanes and alkenes in organic chemistry is evident in their reactivity. Alkenes will decolorize bromine water as they form bonds with it, while alkanes do not.
Vocabulary: Unsaturated hydrocarbons are compounds that contain at least one carbon-carbon double or triple bond, allowing them to undergo addition reactions.
Structural Formulas of Alkenes
Alkenes have specific structural formulas that illustrate their double bond placement. Understanding these structures is crucial for predicting their properties and reactions.
- Ethene (C₂H₄): H₂C=CH₂
- Propene (C₃H₆): H₃C-CH=CH₂
- Butene (C₄H₈): H₃C-CH₂-CH=CH₂ or H₃C-CH=CH-CH₃
Highlight: In butene, the double bond can be in different positions, leading to different isomers.
Example: The general formula for alkenes with one double bond is CnH₂n, where n is the number of carbon atoms.
Understanding the structural differences between alkanes and alkenes is crucial for predicting their behavior in chemical reactions and their uses in organic chemistry.
Fractional Distillation of Crude Oil
The fractional distillation process for crude oil is a fundamental technique in the petroleum industry. Crude oil, a mixture of hydrocarbons, is separated into different fractions based on their boiling points. This process takes place in a fractionating column, where heated crude oil is introduced at the bottom.
Definition: Fractional distillation is a physical process that separates crude oil into fractions containing compounds with similar carbon chain lengths.
The properties of hydrocarbons depend on their size:
- Larger hydrocarbons condense more quickly due to higher boiling points
- Smaller molecules condense higher up the column
- As molecule size decreases:
- Boiling point lowers
- Flammability increases
- Viscosity decreases
- Volatility increases
Highlight: The fractional distillation of crude oil diagram illustrates how different fractions are tapped off at various levels where they condense.
Vocabulary: Viscosity refers to a fluid's resistance to flow, with less viscous substances being less "gloopy" and flowing more easily.
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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.
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Anna
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Best app on earth! no words because it’s too good
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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.
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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
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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!
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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.
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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.
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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
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THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. 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 Knowunity AI. 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
Crude Oil Magic: How Fractional Distillation Turns Oil into Different Fuels
Tanaka Machiridza
@tanakamachiridza
Crude oil is a complex mixture of hydrocarbons that can be separated through fractional distillation process for crude oil. This process allows for the extraction of various useful products with different properties. The resulting fractions have distinct characteristics based... Show more
Burning Hydrocarbons
Hydrocarbons serve as important fuels due to their ability to release useful energy when reacted with oxygen. This process is known as combustion.
Definition: A fuel is a substance that reacts with oxygen to release useful energy.
Complete combustion occurs when there is an abundance of oxygen. The products of complete combustion of any hydrocarbon in oxygen are carbon dioxide and water.
Example: The balanced symbol equation for the complete combustion of methane (CH₄) is: CH₄ + 2O₂ → CO₂ + 2H₂O + energy
Highlight: It's crucial to ensure that the number of carbon, hydrogen, and oxygen atoms are the same on both sides of the equation.
Vocabulary: Volatile hydrocarbons are those that evaporate readily, posing a significant fire risk. This is why smoking is prohibited at petrol stations.
Sign up to see the contentIt's free!
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Demonstrating Combustion Products
To demonstrate that a hydrocarbon fuel burns to produce carbon dioxide and water, a specific experimental setup can be used. This setup involves burning hexane and collecting the combustion products.
- A water pump draws gases from the burning hexane through the apparatus.
- Water collects inside a cooled U-tube, which can be identified by checking its boiling point.
- Limewater turns milky when carbon dioxide passes through it, indicating the presence of CO₂.
Example: In this experiment, hexane is used as the hydrocarbon fuel. The combustion products are passed through crushed ice and water to cool them, allowing water vapor to condense in the U-tube.
Highlight: This practical demonstration provides visual evidence of the products formed during the complete combustion of hydrocarbons.
Sign up to see the contentIt's free!
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Alkanes: Saturated Hydrocarbons
Alkanes are an important class of hydrocarbons found in crude oil. They have distinct properties based on their structure.
Definition: Alkanes are hydrocarbons made up of chains of carbon atoms joined by single covalent bonds, surrounded by hydrogen atoms.
Key characteristics of alkanes:
- They have the general formula CnH₂n+₂
- All carbon-carbon bonds are single bonds
- They are called saturated hydrocarbons because they have no spare bonds
Example: Methane (CH₄) and ethane (C₂H₆) are examples of alkanes.
Highlight: The difference between alkanes and alkenes can be determined by adding the substance to bromine water. Alkanes won't decolorize the bromine water as they have no spare bonds to react with bromine.
Vocabulary: Saturated hydrocarbons are compounds in which all carbon atoms are joined by single bonds, leaving no room for additional atoms to be added without breaking existing bonds.
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Alkenes: Unsaturated Hydrocarbons
Alkenes are another important class of hydrocarbons found in crude oil. They differ from alkanes in their structure and properties.
Definition: Alkenes are hydrocarbons with chains of carbon atoms containing one or more double covalent bonds.
Key characteristics of alkenes:
- They have the general formula CnH₂n for those containing one double bond
- They are more reactive than alkanes due to their double bond
- They can form polymers by opening their double bonds
- They are called unsaturated hydrocarbons as their double bonds can open up and allow other atoms to join
Example: The first three alkenes are ethene (C₂H₄), propene (C₃H₆), and butene (C₄H₈).
Highlight: The difference between alkanes and alkenes in organic chemistry is evident in their reactivity. Alkenes will decolorize bromine water as they form bonds with it, while alkanes do not.
Vocabulary: Unsaturated hydrocarbons are compounds that contain at least one carbon-carbon double or triple bond, allowing them to undergo addition reactions.
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Structural Formulas of Alkenes
Alkenes have specific structural formulas that illustrate their double bond placement. Understanding these structures is crucial for predicting their properties and reactions.
- Ethene (C₂H₄): H₂C=CH₂
- Propene (C₃H₆): H₃C-CH=CH₂
- Butene (C₄H₈): H₃C-CH₂-CH=CH₂ or H₃C-CH=CH-CH₃
Highlight: In butene, the double bond can be in different positions, leading to different isomers.
Example: The general formula for alkenes with one double bond is CnH₂n, where n is the number of carbon atoms.
Understanding the structural differences between alkanes and alkenes is crucial for predicting their behavior in chemical reactions and their uses in organic chemistry.
Sign up to see the contentIt's free!
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Improve your grades
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Fractional Distillation of Crude Oil
The fractional distillation process for crude oil is a fundamental technique in the petroleum industry. Crude oil, a mixture of hydrocarbons, is separated into different fractions based on their boiling points. This process takes place in a fractionating column, where heated crude oil is introduced at the bottom.
Definition: Fractional distillation is a physical process that separates crude oil into fractions containing compounds with similar carbon chain lengths.
The properties of hydrocarbons depend on their size:
- Larger hydrocarbons condense more quickly due to higher boiling points
- Smaller molecules condense higher up the column
- As molecule size decreases:
- Boiling point lowers
- Flammability increases
- Viscosity decreases
- Volatility increases
Highlight: The fractional distillation of crude oil diagram illustrates how different fractions are tapped off at various levels where they condense.
Vocabulary: Viscosity refers to a fluid's resistance to flow, with less viscous substances being less "gloopy" and flowing more easily.
We thought you’d never ask...
What is the Knowunity AI companion?
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.
Where can I download the Knowunity app?
You can download the app from Google Play Store and Apple App Store.
Is Knowunity really free of charge?
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App Store
4.7/5
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 Knowunity AI. 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 Knowunity AI. 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