Quantitative Chemistry is a crucial area of study that involves... Show more
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Sophia + Charlotte
30/07/2025
Chemistry
Quantitative chemistry
2,443
•
30 Jul 2025
•
Fun Chemistry: Solve Moles, Reagents, and Mass Problems!
Moles, Equations, and Limiting Reagents
This page delves deeper into quantitative chemistry equations, focusing on reacting masses, limiting reagents, and gas calculations.
Reacting masses can be calculated using mole ratios from balanced equations. An example is provided for the production of ammonia:
Example: N₂ + 3H₂ → 2NH₃ Given 280g of nitrogen gas, the calculation shows that 340g of ammonia can be produced.
The concept of limiting reagents is introduced, explaining that reactions stop when one reactant is completely consumed.
Definition: The limiting reagent is the reactant that is completely used up in a reaction and determines the amount of product formed.
A practical example is given using the reaction between titanium chloride and sodium:
Example: TiCl₄ + 4Na → Ti + 4NaCl 40kg of titanium chloride is the limiting reagent when reacted with 20kg of sodium.
Gas calculations are explained, noting that one mole of any gas occupies 24 dm³ at room temperature (20°C).
Highlight: Volume of gas = (Mass of gas x 24) / Mr of gas
The page concludes with an introduction to concentration calculations, defining concentration as the measure of solute quantity dissolved in a given amount of solvent.
Vocabulary: Concentration is expressed in units of g/dm³ or mol/dm³.
Advanced Quantitative Chemistry Concepts
This final page covers more advanced topics in quantitative chemistry, including complex concentration calculations, atom economy, and percentage yield.
A detailed example of a concentration calculation is provided, involving the neutralization of sulfuric acid with sodium hydroxide:
Example: 2NaOH + H₂SO₄ → Na₂SO₄ + 2H₂O The concentration of H₂SO₄ is calculated to be 0.0417 mol/dm³.
The conversion between mol/dm³ and g/dm³ is explained:
Highlight: Mass = moles x Mr
Atom economy is introduced as a measure of reaction efficiency:
Definition: Atom economy = (relative formula mass of desired products / relative formula mass of all reactants) x 100
An example calculation for atom economy is provided for the production of hydrogen gas:
Example: CH₄ (g) + H₂O (g) → CO (g) + 3H₂ (g) Atom economy is calculated as 17.6%
Finally, the concept of percentage yield is explained:
Definition: Percentage yield = (mass of product actually made / maximum theoretical mass of product) x 100
The guide notes that yields are always less than 100% due to various factors, including reversible reactions.
Highlight: "Yields are always less than 100. Some product or reactant always gets lost along the way."
This comprehensive guide covers essential topics in quantitative chemistry, providing students with the knowledge and skills needed to solve complex chemical calculations and understand the efficiency of chemical processes.
Quantitative Chemistry Fundamentals
This page introduces fundamental concepts in quantitative chemistry, focusing on calculations involving compounds and chemical reactions.
The relative formula mass (Mr) of a compound is calculated by adding the relative atomic masses of all atoms in the compound. For example, the Mr of MgCl₂ is calculated as follows:
Example: Mr of MgCl₂ = 24 + (35.5 x 2) = 95
The percentage mass of an element in a compound is determined using the formula:
Definition: Percentage mass of an element = (Ar x number of atoms of that element x 100) / Mr of the compound
The concept of the mole is introduced as a measure of the amount of substance.
Vocabulary: The mole is the amount of substance containing Avogadro's number (6.02 x 10²³) of particles.
The relationship between mass, moles, and relative atomic/molecular mass is expressed as:
Highlight: Number of moles = mass (g) / Mr (of the element or compound)
The principle of conservation of mass in chemical reactions is explained, emphasizing that atoms are neither created nor destroyed during reactions. This is represented by balanced chemical equations.
Quote: "During a chemical reaction no atoms are destroyed and no atoms are created."
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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
Fun Chemistry: Solve Moles, Reagents, and Mass Problems!
Quantitative Chemistry is a crucial area of study that involves calculations and numerical analysis of chemical reactions and compounds. This guide covers key concepts including relative formula mass, percentage composition, moles, conservation of mass, reacting masses, limiting reagents, gas calculations,... Show more
Moles, Equations, and Limiting Reagents
This page delves deeper into quantitative chemistry equations, focusing on reacting masses, limiting reagents, and gas calculations.
Reacting masses can be calculated using mole ratios from balanced equations. An example is provided for the production of ammonia:
Example: N₂ + 3H₂ → 2NH₃ Given 280g of nitrogen gas, the calculation shows that 340g of ammonia can be produced.
The concept of limiting reagents is introduced, explaining that reactions stop when one reactant is completely consumed.
Definition: The limiting reagent is the reactant that is completely used up in a reaction and determines the amount of product formed.
A practical example is given using the reaction between titanium chloride and sodium:
Example: TiCl₄ + 4Na → Ti + 4NaCl 40kg of titanium chloride is the limiting reagent when reacted with 20kg of sodium.
Gas calculations are explained, noting that one mole of any gas occupies 24 dm³ at room temperature (20°C).
Highlight: Volume of gas = (Mass of gas x 24) / Mr of gas
The page concludes with an introduction to concentration calculations, defining concentration as the measure of solute quantity dissolved in a given amount of solvent.
Vocabulary: Concentration is expressed in units of g/dm³ or mol/dm³.
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
Advanced Quantitative Chemistry Concepts
This final page covers more advanced topics in quantitative chemistry, including complex concentration calculations, atom economy, and percentage yield.
A detailed example of a concentration calculation is provided, involving the neutralization of sulfuric acid with sodium hydroxide:
Example: 2NaOH + H₂SO₄ → Na₂SO₄ + 2H₂O The concentration of H₂SO₄ is calculated to be 0.0417 mol/dm³.
The conversion between mol/dm³ and g/dm³ is explained:
Highlight: Mass = moles x Mr
Atom economy is introduced as a measure of reaction efficiency:
Definition: Atom economy = (relative formula mass of desired products / relative formula mass of all reactants) x 100
An example calculation for atom economy is provided for the production of hydrogen gas:
Example: CH₄ (g) + H₂O (g) → CO (g) + 3H₂ (g) Atom economy is calculated as 17.6%
Finally, the concept of percentage yield is explained:
Definition: Percentage yield = (mass of product actually made / maximum theoretical mass of product) x 100
The guide notes that yields are always less than 100% due to various factors, including reversible reactions.
Highlight: "Yields are always less than 100. Some product or reactant always gets lost along the way."
This comprehensive guide covers essential topics in quantitative chemistry, providing students with the knowledge and skills needed to solve complex chemical calculations and understand the efficiency of chemical processes.
Quantitative Chemistry Fundamentals
This page introduces fundamental concepts in quantitative chemistry, focusing on calculations involving compounds and chemical reactions.
The relative formula mass (Mr) of a compound is calculated by adding the relative atomic masses of all atoms in the compound. For example, the Mr of MgCl₂ is calculated as follows:
Example: Mr of MgCl₂ = 24 + (35.5 x 2) = 95
The percentage mass of an element in a compound is determined using the formula:
Definition: Percentage mass of an element = (Ar x number of atoms of that element x 100) / Mr of the compound
The concept of the mole is introduced as a measure of the amount of substance.
Vocabulary: The mole is the amount of substance containing Avogadro's number (6.02 x 10²³) of particles.
The relationship between mass, moles, and relative atomic/molecular mass is expressed as:
Highlight: Number of moles = mass (g) / Mr (of the element or compound)
The principle of conservation of mass in chemical reactions is explained, emphasizing that atoms are neither created nor destroyed during reactions. This is represented by balanced chemical equations.
Quote: "During a chemical reaction no atoms are destroyed and no atoms are created."
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.
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