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27
0
Zainab
15/10/2025
Chemistry
GCSE Chemical Analysis
893
•
15 Oct 2025
•
Zainab
@zainab_02839
Chemical Analysis in GCSE Chemistry: Purity, Formulations, and Chromatography
This... Show more
This page continues the discussion on chromatography and introduces methods for identifying common gases, which are crucial topics for GCSE chemical analysis active recall questions.
The chromatography method is further elaborated, explaining why some soluble dyes travel faster or slower through the paper. This information is vital for understanding how to know if a substance is pure in chromatography.
Definition: More soluble dyes travel faster as they spend more time in the mobile phase, while less soluble dyes travel slower due to greater attraction to the paper (stationary phase).
The document then transitions to the identification of common gases, providing simple tests for oxygen, chlorine, carbon dioxide, and hydrogen. These tests are essential for students to know how to identify a substance in chemistry.
Example:
- Oxygen: A glowing splint relights
- Chlorine: Damp litmus paper is bleached
- Carbon Dioxide: Limewater turns cloudy/milky
- Hydrogen: Produces a squeaky pop sound
The page also covers the identification of ions through chemical and spectroscopic means. It provides information on the flame colors produced by various cations, which is a key aspect of liquid chromatography methods for GCSE chemistry students.
Highlight: Different cations produce distinct flame colors:
- Lithium ions: Crimson
- Sodium ions: Yellow
- Potassium ions: Lilac
- Calcium ions: Orange-red
- Copper ions: Green
The document further explains the color changes observed when sodium hydroxide (NaOH) is added to different cations, providing another method for ion identification.
This final page focuses on advanced ion identification techniques and introduces instrumental methods in chemical analysis, which are crucial for GCSE chemical analysis active recall questions and answers.
The document provides detailed information on how to test for specific ions:
Example:
- Chloride ions form a white precipitate of silver chloride
- Bromide ions form a cream precipitate of silver bromide
- Iodide ions form a yellow precipitate of silver iodide
The page then introduces Flame Emission Spectroscopy, an advanced technique used to identify ions in solutions and measure their concentrations. This method is particularly relevant for students learning how to test for purity in AQA chemistry.
Definition: Flame Emission Spectroscopy works by placing a sample into a flame, where ions heat up and electrons gain energy. As electrons return to their original energy levels, they transfer energy as light, producing a characteristic line spectrum.
The intensity of the spectrum can be used to determine the concentration of the ion, making this technique valuable for both qualitative and quantitative analysis.
Finally, the document discusses instrumental methods in chemical analysis, which are tests that use machines. These methods offer several advantages over traditional chemical tests:
This information is crucial for students to understand the modern approaches to how to tell if a substance is pure or impure in advanced chemical analysis.
This page introduces fundamental concepts in chemical analysis, focusing on purity, formulations, and chromatography. It provides essential information for students studying GCSE chemical analysis.
The concept of purity in chemistry is explained as a single element or compound not mixed with any other substance. Students learn how to determine the purity of a substance by measuring its melting or boiling point and comparing it to the known values for the pure substance. The closer the measured point is to the reference value, the purer the substance.
Highlight: Impurities can lower the melting point of a substance and cause a broader melting point range.
The document then introduces formulations, which are useful mixtures created for specific purposes following a precise formula. These are made by carefully measuring and mixing components to achieve desired properties.
Example: Examples of formulations include fuels, cleaning agents, paints, medicines, alloys, fertilizers, and foods.
Chromatography, a crucial technique in GCSE chemistry, is presented as a method for separating mixtures and identifying substances. The process involves two phases:
Vocabulary: Rf value - The ratio between the distance traveled by the dissolved substance and the distance traveled by the solvent.
The document explains how to calculate the Rf value and use it to differentiate between pure and impure substances. A pure substance produces a single spot on the chromatogram, while an impure substance results in multiple spots.
The page concludes with a step-by-step method for performing chromatography, which is essential knowledge for the AQA GCSE Chemistry chromatography Required practical.
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.
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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
15 Oct 2025
893
3 pages
Zainab @zainab_02839
Chemical Analysis in GCSE Chemistry: Purity, Formulations, and Chromatography
This document covers key concepts in chemical analysis for GCSE Chemistry, focusing on purity, formulations, chromatography, and identification of substances. It... Show more
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
This page continues the discussion on chromatography and introduces methods for identifying common gases, which are crucial topics for GCSE chemical analysis active recall questions.
The chromatography method is further elaborated, explaining why some soluble dyes travel faster or slower through the paper. This information is vital for understanding how to know if a substance is pure in chromatography.
Definition More soluble dyes travel faster as they spend more time in the mobile phase, while less soluble dyes travel slower due to greater attraction to the paper (stationary phase).
The document then transitions to the identification of common gases, providing simple tests for oxygen, chlorine, carbon dioxide, and hydrogen. These tests are essential for students to know how to identify a substance in chemistry.
Example
- Oxygen A glowing splint relights
- Chlorine Damp litmus paper is bleached
- Carbon Dioxide Limewater turns cloudy/milky
- Hydrogen Produces a squeaky pop sound
The page also covers the identification of ions through chemical and spectroscopic means. It provides information on the flame colors produced by various cations, which is a key aspect of liquid chromatography methods for GCSE chemistry students.
Highlight Different cations produce distinct flame colors
- Lithium ions Crimson
- Sodium ions Yellow
- Potassium ions Lilac
- Calcium ions Orange-red
- Copper ions Green
The document further explains the color changes observed when sodium hydroxide (NaOH) is added to different cations, providing another method for ion identification.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
This final page focuses on advanced ion identification techniques and introduces instrumental methods in chemical analysis, which are crucial for GCSE chemical analysis active recall questions and answers.
The document provides detailed information on how to test for specific ions
Example
- Chloride ions form a white precipitate of silver chloride
- Bromide ions form a cream precipitate of silver bromide
- Iodide ions form a yellow precipitate of silver iodide
The page then introduces Flame Emission Spectroscopy, an advanced technique used to identify ions in solutions and measure their concentrations. This method is particularly relevant for students learning how to test for purity in AQA chemistry.
Definition Flame Emission Spectroscopy works by placing a sample into a flame, where ions heat up and electrons gain energy. As electrons return to their original energy levels, they transfer energy as light, producing a characteristic line spectrum.
The intensity of the spectrum can be used to determine the concentration of the ion, making this technique valuable for both qualitative and quantitative analysis.
Finally, the document discusses instrumental methods in chemical analysis, which are tests that use machines. These methods offer several advantages over traditional chemical tests
This information is crucial for students to understand the modern approaches to how to tell if a substance is pure or impure in advanced chemical analysis.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
This page introduces fundamental concepts in chemical analysis, focusing on purity, formulations, and chromatography. It provides essential information for students studying GCSE chemical analysis.
The concept of purity in chemistry is explained as a single element or compound not mixed with any other substance. Students learn how to determine the purity of a substance by measuring its melting or boiling point and comparing it to the known values for the pure substance. The closer the measured point is to the reference value, the purer the substance.
Highlight Impurities can lower the melting point of a substance and cause a broader melting point range.
The document then introduces formulations, which are useful mixtures created for specific purposes following a precise formula. These are made by carefully measuring and mixing components to achieve desired properties.
Example Examples of formulations include fuels, cleaning agents, paints, medicines, alloys, fertilizers, and foods.
Chromatography, a crucial technique in GCSE chemistry, is presented as a method for separating mixtures and identifying substances. The process involves two phases
Vocabulary Rf value - The ratio between the distance traveled by the dissolved substance and the distance traveled by the solvent.
The document explains how to calculate the Rf value and use it to differentiate between pure and impure substances. A pure substance produces a single spot on the chromatogram, while an impure substance results in multiple spots.
The page concludes with a step-by-step method for performing chromatography, which is essential knowledge for the AQA GCSE Chemistry chromatography Required practical.
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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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
