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5 Dec 2025
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Mass Calculations Using Balanced Chemical Equations
S
SJ
@sj_hkza
![Calculations from Balanced Equations
1] Calculate the mass of hydrogen produced by dissolving 0.2g of magnesium in excess sulphuric acid sol](/_next/image?url=https%3A%2F%2Fcontent-eu-central-1.knowunity.com%2FCONTENT%2FPaoOhpueGKEtXEKVEcBf_image_page_1.webp&w=2048&q=75)
Calculating Mass from Balanced Equations - Magnesium Example
When magnesium reacts with sulphuric acid, you can calculate exactly how much hydrogen gas will be produced. The key is following a systematic approach that breaks down the problem into manageable steps.
Start with your balanced equation: Mg + H₂SO₄ → MgSO₄ + H₂. Always check the equation is balanced first - this one already is! Next, identify what you're given (0.2g of magnesium) and what you need to find (mass of hydrogen).
Calculate the moles of magnesium using n = m/GFM. With magnesium's GFM being 24.5, you get n = 0.2/24.5 = 0.008163 mol. The mole ratio from the equation shows 1:1 between Mg and H₂, so you'll also get 0.008163 mol of hydrogen.
Finally, convert moles of hydrogen back to mass using m = n × GFM. With hydrogen's GFM of 2, the answer is 0.008163 × 2 = 0.016g of hydrogen. This step-by-step method works for any similar calculation!
Remember: The mole ratio from your balanced equation is the bridge between reactants and products - it's absolutely crucial for getting the right answer.
![Calculations from Balanced Equations
1] Calculate the mass of hydrogen produced by dissolving 0.2g of magnesium in excess sulphuric acid sol](/_next/image?url=https%3A%2F%2Fcontent-eu-central-1.knowunity.com%2FCONTENT%2FPaoOhpueGKEtXEKVEcBf_image_page_2.webp&w=2048&q=75)
Iron Oxide Reduction Calculation
Reducing iron oxide with carbon monoxide is a classic industrial process, and you can calculate the iron yield using the same systematic approach. The balanced equation Fe₂O₃ + 3CO → 3CO + 2Fe shows the stoichiometric relationships you need.
Starting with 6.4g of iron(III) oxide, calculate its moles first. The GFM of Fe₂O₃ is (56×2) + (16×3) = 160, giving you n = 6.4/160 = 0.04 mol of iron oxide.
The mole ratio is crucial here - notice that 1 mole of Fe₂O₃ produces 2 moles of Fe. So 0.04 mol of iron oxide will produce 0.04 × 2 = 0.08 mol of iron. This 1:2 ratio comes directly from the balanced equation.
Convert the moles of iron to mass using iron's GFM of 56: m = 0.08 × 56 = 4.48g of iron. Notice how the mole ratio determines your final answer - getting this step right is essential for exam success.
Top Tip: Always double-check your mole ratios from the balanced equation - they're often where students make mistakes in calculations.
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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.
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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.
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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
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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
Mass Calculations Using Balanced Chemical Equations
S
SJ
@sj_hkza
Ever wondered how chemists work out exactly how much product they'll get from a reaction? These calculations help you predict quantities in chemical reactions using balanced equations - a crucial skill for your chemistry exams and practical work.
Calculating Mass from Balanced Equations - Magnesium Example
When magnesium reacts with sulphuric acid, you can calculate exactly how much hydrogen gas will be produced. The key is following a systematic approach that breaks down the problem into manageable steps.
Start with your balanced equation: Mg + H₂SO₄ → MgSO₄ + H₂. Always check the equation is balanced first - this one already is! Next, identify what you're given (0.2g of magnesium) and what you need to find (mass of hydrogen).
Calculate the moles of magnesium using n = m/GFM. With magnesium's GFM being 24.5, you get n = 0.2/24.5 = 0.008163 mol. The mole ratio from the equation shows 1:1 between Mg and H₂, so you'll also get 0.008163 mol of hydrogen.
Finally, convert moles of hydrogen back to mass using m = n × GFM. With hydrogen's GFM of 2, the answer is 0.008163 × 2 = 0.016g of hydrogen. This step-by-step method works for any similar calculation!
Remember: The mole ratio from your balanced equation is the bridge between reactants and products - it's absolutely crucial for getting the right answer.
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Iron Oxide Reduction Calculation
Reducing iron oxide with carbon monoxide is a classic industrial process, and you can calculate the iron yield using the same systematic approach. The balanced equation Fe₂O₃ + 3CO → 3CO + 2Fe shows the stoichiometric relationships you need.
Starting with 6.4g of iron(III) oxide, calculate its moles first. The GFM of Fe₂O₃ is (56×2) + (16×3) = 160, giving you n = 6.4/160 = 0.04 mol of iron oxide.
The mole ratio is crucial here - notice that 1 mole of Fe₂O₃ produces 2 moles of Fe. So 0.04 mol of iron oxide will produce 0.04 × 2 = 0.08 mol of iron. This 1:2 ratio comes directly from the balanced equation.
Convert the moles of iron to mass using iron's GFM of 56: m = 0.08 × 56 = 4.48g of iron. Notice how the mole ratio determines your final answer - getting this step right is essential for exam success.
Top Tip: Always double-check your mole ratios from the balanced equation - they're often where students make mistakes in calculations.
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?
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4.9/5
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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