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Britain & the wider world: 1745 -1901
1l the quest for political stability: germany, 1871-1991
The cold war
Inter-war germany
Medieval period: 1066 -1509
2d religious conflict and the church in england, c1529-c1570
2o democracy and nazism: germany, 1918-1945
1f industrialisation and the people: britain, c1783-1885
1c the tudors: england, 1485-1603
2m wars and welfare: britain in transition, 1906-1957
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2s the making of modern britain, 1951-2007
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Chemistry
6 Dec 2025
216
2 pages
AK Squad @aksquad_hoka
Ever wondered why baking recipes are so precise or how scientists know exactly how much product they'll get... Show more
The law of conservation of mass is your starting point for all quantitative chemistry. Simply put, atoms don't vanish or appear from nowhere during reactions - what goes in must come out.
Relative Formula Mass (RFM) is just adding up all the atomic masses in a compound. Take MgCl₂ magnesium is 24, each chlorine is 35.5, so 24 + (2 × 35.5) = 95. Easy!
To find the percentage mass of an element, use this approach mass of element ÷ RFM × 100. For sodium in Na₂CO₃, that's (2 × 23) ÷ 106 × 100 = 43%. If a reaction seems to gain or lose mass, don't panic - there's probably a gas involved that wasn't measured.
Quick tip The mole is just a massive number (6.02 × 10²³) that helps us count atoms. One mole of any element weighs exactly its relative atomic mass in grams.
Balancing equations using masses follows a simple pattern convert masses to moles, find the smallest number, then divide everything by it. If you don't get whole numbers, multiply everything until you do.
The limiting reactant is like the weakest link in a chain - it runs out first and stops the whole reaction. Think of it like making sandwiches if you have 10 slices of bread but only 3 pieces of ham, you can only make 3 sandwiches (ham is your limiting reactant).
When calculating product masses, follow these steps write the balanced equation, work out the RFMs, convert your known mass to moles, use the equation ratios to find moles of product, then convert back to mass.
Remember The amount of product you get depends entirely on your limiting reactant - double it, and you'll double your product!
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.
5
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Explore the Law of Conservation of Mass in this detailed summary, covering key concepts such as balanced equations, chemical reactions, and the differences between closed and non-enclosed systems. Ideal for GCSE Chemistry students, this resource provides essential insights into how mass is conserved during chemical reactions.
ChemistryExplore essential chemistry calculations involving moles, mass, concentration, and volume. This summary covers key concepts such as molar mass, stoichiometry, and mole conversions, providing a clear understanding of how to calculate the amounts of substances in chemical reactions. Ideal for students preparing for exams or needing a quick reference.
ChemistryExplore 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.
BiologyExplore the fundamentals of balancing chemical equations and understanding moles in this concise study resource. Key topics include the law of conservation of mass, relative formula mass (RFM), and stoichiometry. Ideal for students looking to master quantitative chemistry concepts and improve their problem-solving skills in chemical reactions.
ChemistryExplore key concepts in Quantitative Chemistry, including mole calculations, limiting reactants, concentration, and percentage yield. This comprehensive summary covers essential principles such as the law of conservation of mass, balancing equations, and atom economy, making it an invaluable resource for GCSE chemistry students.
ChemistryExplore key concepts in Quantitative Chemistry, including moles, limiting reactants, atom economy, and percentage yield. This summary covers essential calculations, definitions, and principles crucial for mastering GCSE AQA Higher Triple Chemistry. Ideal for exam preparation and active recall.
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
AK Squad
@aksquad_hoka
Ever wondered why baking recipes are so precise or how scientists know exactly how much product they'll get from a reaction? Quantitative chemistry is all about the maths behind chemical reactions - and it's way more useful than you might... Show more
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The law of conservation of mass is your starting point for all quantitative chemistry. Simply put, atoms don't vanish or appear from nowhere during reactions - what goes in must come out.
Relative Formula Mass (RFM) is just adding up all the atomic masses in a compound. Take MgCl₂: magnesium is 24, each chlorine is 35.5, so 24 + (2 × 35.5) = 95. Easy!
To find the percentage mass of an element, use this approach: mass of element ÷ RFM × 100. For sodium in Na₂CO₃, that's (2 × 23) ÷ 106 × 100 = 43%. If a reaction seems to gain or lose mass, don't panic - there's probably a gas involved that wasn't measured.
Quick tip: The mole is just a massive number (6.02 × 10²³) that helps us count atoms. One mole of any element weighs exactly its relative atomic mass in grams.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Balancing equations using masses follows a simple pattern: convert masses to moles, find the smallest number, then divide everything by it. If you don't get whole numbers, multiply everything until you do.
The limiting reactant is like the weakest link in a chain - it runs out first and stops the whole reaction. Think of it like making sandwiches: if you have 10 slices of bread but only 3 pieces of ham, you can only make 3 sandwiches (ham is your limiting reactant).
When calculating product masses, follow these steps: write the balanced equation, work out the RFMs, convert your known mass to moles, use the equation ratios to find moles of product, then convert back to mass.
Remember: The amount of product you get depends entirely on your limiting reactant - double it, and you'll double your product!
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.
5
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Explore the Law of Conservation of Mass in this detailed summary, covering key concepts such as balanced equations, chemical reactions, and the differences between closed and non-enclosed systems. Ideal for GCSE Chemistry students, this resource provides essential insights into how mass is conserved during chemical reactions.
ChemistryExplore essential chemistry calculations involving moles, mass, concentration, and volume. This summary covers key concepts such as molar mass, stoichiometry, and mole conversions, providing a clear understanding of how to calculate the amounts of substances in chemical reactions. Ideal for students preparing for exams or needing a quick reference.
ChemistryExplore 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.
BiologyExplore the fundamentals of balancing chemical equations and understanding moles in this concise study resource. Key topics include the law of conservation of mass, relative formula mass (RFM), and stoichiometry. Ideal for students looking to master quantitative chemistry concepts and improve their problem-solving skills in chemical reactions.
ChemistryExplore key concepts in Quantitative Chemistry, including mole calculations, limiting reactants, concentration, and percentage yield. This comprehensive summary covers essential principles such as the law of conservation of mass, balancing equations, and atom economy, making it an invaluable resource for GCSE chemistry students.
ChemistryExplore key concepts in Quantitative Chemistry, including moles, limiting reactants, atom economy, and percentage yield. This summary covers essential calculations, definitions, and principles crucial for mastering GCSE AQA Higher Triple Chemistry. Ideal for exam preparation and active recall.
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
