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Chemistry

4 Dec 2025

479

2 pages

Understanding Fractional Distillation

L

lydia wilton @lydiawilton_deay

Fractional distillation is the key process that turns crude oil into the useful products we use every day.... Show more

T
5
tuesday 3rd June 2019
6
1. heat crude oil
2. the mixture of liquids will produce vapours, (gas)
Liquids with lower boiling points vapour

How Fractional Distillation Works

Ever wondered how we get petrol for cars from thick black crude oil? It's all about fractional distillation! This process splits crude oil into useful products by heating it and separating the components.

The process begins by heating crude oil to high temperatures (around 350°C). When heated, different parts of the crude oil turn into vapours at different temperatures. The shorter chain hydrocarbons (like those in petrol) have lower boiling points, so they vapourise first and rise to the top of the fractionating column.

Meanwhile, the longer chain hydrocarbons (like those in diesel and bitumen) have higher boiling points. They vapourise last and stay near the bottom of the column. As the vapours rise through the column, they cool and condense at different heights depending on their boiling points.

Remember this Temperature decreases as you move up the fractionating column! The top is cool (about 25°C) while the bottom remains hot (around 350°C).

The whole process works because different hydrocarbons have different properties. Those with fewer carbon atoms require less energy to boil, while those with more carbon atoms need more energy to break their stronger bonds.

T
5
tuesday 3rd June 2019
6
1. heat crude oil
2. the mixture of liquids will produce vapours, (gas)
Liquids with lower boiling points vapour

Fractions and Their Uses

The different parts we get from crude oil are called fractions - they're only portions of the original oil but much more useful! Each fraction has unique properties that make it perfect for specific uses.

Small hydrocarbon molecules (like those in gas and petrol) have weak forces holding them together, giving them low boiling points. These are highly volatile substances that flow easily and ignite quickly - perfect for fuels! The largest molecules form bitumen, which hardly flows at all and is difficult to ignite.

The main fractions we get include liquefied petroleum gas (LPG) for heating and cooking, petrol for cars, kerosene for aircraft, diesel for cars and trains, heavy fuel oil for ships and power stations, and bitumen for roads and roofs.

Quick tip Try this memory aid for the fractions from top to bottom "Lazy Penguins Keep Drinking Hot Beer" for LPG, Petrol, Kerosene, Diesel, Heavy fuel oil, and Bitumen!

The properties of each fraction directly relate to their uses. Petrol needs to ignite easily in car engines, while bitumen needs to be solid and waterproof for road surfaces. This is why separating crude oil is so important - it gives us exactly what we need for different purposes.

We thought you’d never ask...

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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?

That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.

Most popular content: Separations and Purifications

Most popular content in Chemistry

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Can't find what you're looking for? Explore other subjects.

Students love us — and so will you.

4.9/5

App Store

4.8/5

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 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

 

Chemistry

479

4 Dec 2025

2 pages

Understanding Fractional Distillation

L

lydia wilton

@lydiawilton_deay

Fractional distillation is the key process that turns crude oil into the useful products we use every day. This process separates crude oil into different fractions based on their boiling points, giving us everything from petrol for cars to bitumen... Show more

T
5
tuesday 3rd June 2019
6
1. heat crude oil
2. the mixture of liquids will produce vapours, (gas)
Liquids with lower boiling points vapour

Sign up to see the contentIt's free!

Access to all documents

Improve your grades

Join milions of students

By signing up you accept Terms of Service and Privacy Policy

How Fractional Distillation Works

Ever wondered how we get petrol for cars from thick black crude oil? It's all about fractional distillation! This process splits crude oil into useful products by heating it and separating the components.

The process begins by heating crude oil to high temperatures (around 350°C). When heated, different parts of the crude oil turn into vapours at different temperatures. The shorter chain hydrocarbons (like those in petrol) have lower boiling points, so they vapourise first and rise to the top of the fractionating column.

Meanwhile, the longer chain hydrocarbons (like those in diesel and bitumen) have higher boiling points. They vapourise last and stay near the bottom of the column. As the vapours rise through the column, they cool and condense at different heights depending on their boiling points.

Remember this: Temperature decreases as you move up the fractionating column! The top is cool (about 25°C) while the bottom remains hot (around 350°C).

The whole process works because different hydrocarbons have different properties. Those with fewer carbon atoms require less energy to boil, while those with more carbon atoms need more energy to break their stronger bonds.

T
5
tuesday 3rd June 2019
6
1. heat crude oil
2. the mixture of liquids will produce vapours, (gas)
Liquids with lower boiling points vapour

Sign up to see the contentIt's free!

Access to all documents

Improve your grades

Join milions of students

By signing up you accept Terms of Service and Privacy Policy

Fractions and Their Uses

The different parts we get from crude oil are called fractions - they're only portions of the original oil but much more useful! Each fraction has unique properties that make it perfect for specific uses.

Small hydrocarbon molecules (like those in gas and petrol) have weak forces holding them together, giving them low boiling points. These are highly volatile substances that flow easily and ignite quickly - perfect for fuels! The largest molecules form bitumen, which hardly flows at all and is difficult to ignite.

The main fractions we get include liquefied petroleum gas (LPG) for heating and cooking, petrol for cars, kerosene for aircraft, diesel for cars and trains, heavy fuel oil for ships and power stations, and bitumen for roads and roofs.

Quick tip: Try this memory aid for the fractions from top to bottom: "Lazy Penguins Keep Drinking Hot Beer" for LPG, Petrol, Kerosene, Diesel, Heavy fuel oil, and Bitumen!

The properties of each fraction directly relate to their uses. Petrol needs to ignite easily in car engines, while bitumen needs to be solid and waterproof for road surfaces. This is why separating crude oil is so important - it gives us exactly what we need for different purposes.

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?

That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.

Most popular content: Separations and Purifications

Most popular content in Chemistry

Most popular content

Can't find what you're looking for? Explore other subjects.

Students love us — and so will you.

4.9/5

App Store

4.8/5

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 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