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Chemistry
7 Dec 2025
30
2 pages
Chemistry calculations involving moles, concentrations, and gas volumes are essential skills you'll need for your A-levels. These formulas... Show more
Concentration tells you exactly how much solute is packed into each cubic decimetre of solution - think of it like measuring how strong your squash is. The stronger the concentration, the more solute particles you've got floating about in there.
The key formula you need to master is c = n/v, where c is concentration , n is moles, and v is volume (dm³). This simple equation lets you work out any of these three values if you know the other two.
Standard solutions are your reference points - solutions where you know the exact concentration. You'll make these using a volumetric flask, which gives you super-accurate measurements for your experiments.
Quick Tip To convert between mol/dm³ and g/dm³, multiply or divide by the molar mass (M). This conversion pops up constantly in exam questions!
Here's something brilliant about gases - equal volumes of different gases contain the same number of molecules at the same temperature and pressure. Whether it's oxygen, nitrogen, or carbon dioxide, they all follow this rule.
At room temperature and pressure (RTP), the molar gas volume is always 24.0 dm³/mol. This means one mole of any gas takes up exactly 24 dm³ of space. Use the formulas v(dm³) = n × 24 or v(cm³) = n × 24000 to work out gas volumes quickly.
For more complex situations, you'll need the ideal gas equation pV = nRT. Remember your units here - pressure in pascals, volume in m³, temperature in Kelvin , and R = 8.314 J mol⁻¹K⁻¹.
Unit Watch Always check your units! Convert kPa to Pa by multiplying by 1000, and don't forget to add 273 to Celsius temperatures.
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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Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Explore essential mole calculations and chemical equations for OCR A Chemistry Topic 2. This resource covers stoichiometry, mole conversions, balancing equations, and the ideal gas equation, providing clear formulas and examples to enhance your understanding. Ideal for exam preparation and mastering key concepts in chemistry.
ChemistryExplore Hess's Law, enthalpy changes, and key concepts in reaction dynamics including atom economy, percent yield, and chemical equilibrium. This comprehensive summary covers essential calculations, energy diagrams, and chromatography techniques relevant to Higher Chemistry Unit 3. Ideal for students preparing for exams or seeking to deepen their understanding of chemical processes.
ChemistryExplore essential concepts in Higher Chemistry, including atom economy, dynamic equilibrium, titration techniques, and enthalpy changes. This summary covers calculations for theoretical and actual yields, bond enthalpy, and the impact of reactants in chemical reactions. Ideal for exam preparation and understanding core principles in chemistry.
ChemistryExplore key concepts of dynamic equilibrium, pH calculations, and acid-base titrations in this comprehensive study note. Understand Le Chatelier's Principle, the equilibrium constant, and the differences between strong and weak acids. Ideal for AS/A Level chemistry students preparing for exams.
ChemistryExplore a comprehensive set of exam questions focused on bond enthalpies, enthalpy changes, and chemical thermodynamics. This resource covers key concepts such as the Haber process, standard enthalpy of formation, and energy changes in chemical reactions. Ideal for students preparing for exams in chemistry and thermodynamics.
ChemistryExplore essential concepts in mole calculations, including theoretical yield, percent yield, and stoichiometry. This summary covers key formulas and examples relevant to AQA AS Chemistry, helping students master mole conversions and mass calculations effectively.
ChemistryApp Store
Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
Chemistry calculations involving moles, concentrations, and gas volumes are essential skills you'll need for your A-levels. These formulas help you work out how much of a substance you have and how it behaves in solutions and as gases.
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Concentration tells you exactly how much solute is packed into each cubic decimetre of solution - think of it like measuring how strong your squash is. The stronger the concentration, the more solute particles you've got floating about in there.
The key formula you need to master is c = n/v, where c is concentration , n is moles, and v is volume (dm³). This simple equation lets you work out any of these three values if you know the other two.
Standard solutions are your reference points - solutions where you know the exact concentration. You'll make these using a volumetric flask, which gives you super-accurate measurements for your experiments.
Quick Tip: To convert between mol/dm³ and g/dm³, multiply or divide by the molar mass (M). This conversion pops up constantly in exam questions!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Here's something brilliant about gases - equal volumes of different gases contain the same number of molecules at the same temperature and pressure. Whether it's oxygen, nitrogen, or carbon dioxide, they all follow this rule.
At room temperature and pressure (RTP), the molar gas volume is always 24.0 dm³/mol. This means one mole of any gas takes up exactly 24 dm³ of space. Use the formulas v(dm³) = n × 24 or v(cm³) = n × 24000 to work out gas volumes quickly.
For more complex situations, you'll need the ideal gas equation: pV = nRT. Remember your units here - pressure in pascals, volume in m³, temperature in Kelvin , and R = 8.314 J mol⁻¹K⁻¹.
Unit Watch: Always check your units! Convert kPa to Pa by multiplying by 1000, and don't forget to add 273 to Celsius temperatures.
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.
0
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Explore essential mole calculations and chemical equations for OCR A Chemistry Topic 2. This resource covers stoichiometry, mole conversions, balancing equations, and the ideal gas equation, providing clear formulas and examples to enhance your understanding. Ideal for exam preparation and mastering key concepts in chemistry.
ChemistryExplore Hess's Law, enthalpy changes, and key concepts in reaction dynamics including atom economy, percent yield, and chemical equilibrium. This comprehensive summary covers essential calculations, energy diagrams, and chromatography techniques relevant to Higher Chemistry Unit 3. Ideal for students preparing for exams or seeking to deepen their understanding of chemical processes.
ChemistryExplore essential concepts in Higher Chemistry, including atom economy, dynamic equilibrium, titration techniques, and enthalpy changes. This summary covers calculations for theoretical and actual yields, bond enthalpy, and the impact of reactants in chemical reactions. Ideal for exam preparation and understanding core principles in chemistry.
ChemistryExplore key concepts of dynamic equilibrium, pH calculations, and acid-base titrations in this comprehensive study note. Understand Le Chatelier's Principle, the equilibrium constant, and the differences between strong and weak acids. Ideal for AS/A Level chemistry students preparing for exams.
ChemistryExplore a comprehensive set of exam questions focused on bond enthalpies, enthalpy changes, and chemical thermodynamics. This resource covers key concepts such as the Haber process, standard enthalpy of formation, and energy changes in chemical reactions. Ideal for students preparing for exams in chemistry and thermodynamics.
ChemistryExplore essential concepts in mole calculations, including theoretical yield, percent yield, and stoichiometry. This summary covers key formulas and examples relevant to AQA AS Chemistry, helping students master mole conversions and mass calculations effectively.
ChemistryApp Store
Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
Sociology