Koncentrácia roztokov je základný pojem v chémii, ktorý ti hovorí,... Show more
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Updated Mar 21, 2026
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Koncentrácia Roztokov: Výpočty a Princípy
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Základné pojmy roztokov
Roztoky sú všade okolo nás - od slanej vody až po lieky. Roztok je homogénna zmes rozpúšťadla (väčšinou voda) a rozpustenej látky (napríklad soľ).
Pri práci s roztokmi musíš rozlišovať medzi hmotnosťou rozpustenej látky , hmotnosťou rozpúšťadla a celkovou hmotnosťou roztoku . Pamätaj si: m_r = m_rl + m_rozp.
Pre molárnu koncentráciu potrebuješ poznať látkové množstvo (n), ktoré vypočítaš ako n = m/M, kde M je molárna hmotnosť z periodickej tabuľky.
Tip: Vždy si kontroluj jednotky - to je najčastejšia chyba pri výpočtoch!
Hmotnostný a objemový zlomok
Hmotnostný zlomok (w) ti ukáže, akú časť celkovej hmotnosti roztoku tvorí rozpustená látka. Vypočítaš ho jednoducho: w = m_rl/m_r. Výsledok môžeš vyjadriť aj v percentách vynásobením číslom 100.
Objemový zlomok (φ) funguje podobne, len pracuje s objemami: φ = V_rl/V_r. Stretávaš sa s ním hlavne pri alkoholických nápojoch - napríklad 40% obj. etanolu vo vodke.
Pozor na jednu vec - pri miešaní kvapalín sa objemy nemusia sčítať presne kvôli interakciám molekúl. Preto vždy beri skutočný objem roztoku, nie len súčet objemov zložiek.
Dôležité: Oba zlomky jsou bezrozmerné veličiny - jednotky sa vykrátia!
Molárna koncentrácia
Molárna koncentrácia (c) je najdôležitejší spôsob vyjadrovania koncentrácie v chémii. Hovorí ti, koľko mólov látky je v jednom litri roztoku: c = n_rl/V_r.
Pre výpočet potrebuješ najprv zistiť látkové množstvo: n_rl = m_rl/M_rl. Molárnu hmotnosť nájdeš v periodickej tabuľke sčítaním hmotností všetkých atómov v molekule.
Kľúčové upozornenie: Objem roztoku musí byť vždy v dm³ alebo litroch! Ak máš objem v ml, prepoč ho: 1000 ml = 1 dm³ = 1 l.
Jednotka molárnej koncentrácie je mol/dm³ alebo mol/l. Táto koncentrácia je super užitočná pri chemických reakciách a stechiometrických výpočtoch.
Pamätaj: Trojuholníkový vzorec c = n/V ti pomôže - zakryj to, čo hľadáš!
Praktické príklady - hmotnostný zlomok a molárna koncentrácia
Poď si to vyskúšať na konkrétnom príklade. Ak rozpustíš 25 g NaCl v 225 g vody, celková hmotnosť roztoku bude 250 g. Hmotnostný zlomok vypočítaš ako w = 25/250 = 0,1, čo je 10%.
Pri molárnej koncentrácii je to trochu zložitejšie. Majme 7,3 g HCl v 500 ml roztoku. Najprv vypočítaš molárnu hmotnosť HCl: M_H = 1,01 g/mol, M_Cl = 35,45 g/mol, takže M_HCl = 36,46 g/mol.
Látkové množstvo: n = 7,3/36,46 = 0,200 mol. Objem prepoč na dm³: 500 ml = 0,5 dm³. Molárna koncentrácia: c = 0,200/0,5 = 0,4 mol/dm³.
Tip: Vždy si najprv vypíš známe hodnoty a kontroluj jednotky pred výpočtom!
Objemový zlomok a dôležité poznámky
Pri objemovom zlomku je výpočet priamočiaryy. Ak zmiešaš 75 ml etanolu s vodou a celkový objem je 250 ml, objemový zlomok je φ = 75/250 = 0,3, čo je 30 obj. %.
Najdôležitejšie tipy pre úspech:
- Kontroluj jednotky - hmotnosti musia byť v rovnakých jednotkách, objemy tiež
- Pri molárnej koncentrácii MUSÍ byť objem v dm³!
- Roztok ≠ rozpúšťadlo
Molárnu hmotnosť vždy počítaj z periodickej tabuľky pre konkrétnu látku. Niekedy budeš musieť prepočítavať medzi rôznymi typmi koncentrácií - to sa naučíš neskôr.
Pamätaj: Najčastejšia chyba sú zlé jednotky - vždy si ich skontroluj!
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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 Knowunity AI. 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 Knowunity AI. 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
Koncentrácia Roztokov: Výpočty a Princípy
Koncentrácia roztokov je základný pojem v chémii, ktorý ti hovorí, koľko rozpustenej látky sa nachádza v roztoku. Bez jej pochopenia by si nemohol správne pripravovať roztoky v laboratóriu ani robiť stechiometrické výpočty.
Základné pojmy roztokov
Roztoky sú všade okolo nás - od slanej vody až po lieky. Roztok je homogénna zmes rozpúšťadla (väčšinou voda) a rozpustenej látky (napríklad soľ).
Pri práci s roztokmi musíš rozlišovať medzi hmotnosťou rozpustenej látky , hmotnosťou rozpúšťadla a celkovou hmotnosťou roztoku . Pamätaj si: m_r = m_rl + m_rozp.
Pre molárnu koncentráciu potrebuješ poznať látkové množstvo (n), ktoré vypočítaš ako n = m/M, kde M je molárna hmotnosť z periodickej tabuľky.
Tip: Vždy si kontroluj jednotky - to je najčastejšia chyba pri výpočtoch!
Sign up to see the contentIt's free!
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Hmotnostný a objemový zlomok
Hmotnostný zlomok (w) ti ukáže, akú časť celkovej hmotnosti roztoku tvorí rozpustená látka. Vypočítaš ho jednoducho: w = m_rl/m_r. Výsledok môžeš vyjadriť aj v percentách vynásobením číslom 100.
Objemový zlomok (φ) funguje podobne, len pracuje s objemami: φ = V_rl/V_r. Stretávaš sa s ním hlavne pri alkoholických nápojoch - napríklad 40% obj. etanolu vo vodke.
Pozor na jednu vec - pri miešaní kvapalín sa objemy nemusia sčítať presne kvôli interakciám molekúl. Preto vždy beri skutočný objem roztoku, nie len súčet objemov zložiek.
Dôležité: Oba zlomky jsou bezrozmerné veličiny - jednotky sa vykrátia!
Sign up to see the contentIt's free!
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Molárna koncentrácia
Molárna koncentrácia (c) je najdôležitejší spôsob vyjadrovania koncentrácie v chémii. Hovorí ti, koľko mólov látky je v jednom litri roztoku: c = n_rl/V_r.
Pre výpočet potrebuješ najprv zistiť látkové množstvo: n_rl = m_rl/M_rl. Molárnu hmotnosť nájdeš v periodickej tabuľke sčítaním hmotností všetkých atómov v molekule.
Kľúčové upozornenie: Objem roztoku musí byť vždy v dm³ alebo litroch! Ak máš objem v ml, prepoč ho: 1000 ml = 1 dm³ = 1 l.
Jednotka molárnej koncentrácie je mol/dm³ alebo mol/l. Táto koncentrácia je super užitočná pri chemických reakciách a stechiometrických výpočtoch.
Pamätaj: Trojuholníkový vzorec c = n/V ti pomôže - zakryj to, čo hľadáš!
Sign up to see the contentIt's free!
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Praktické príklady - hmotnostný zlomok a molárna koncentrácia
Poď si to vyskúšať na konkrétnom príklade. Ak rozpustíš 25 g NaCl v 225 g vody, celková hmotnosť roztoku bude 250 g. Hmotnostný zlomok vypočítaš ako w = 25/250 = 0,1, čo je 10%.
Pri molárnej koncentrácii je to trochu zložitejšie. Majme 7,3 g HCl v 500 ml roztoku. Najprv vypočítaš molárnu hmotnosť HCl: M_H = 1,01 g/mol, M_Cl = 35,45 g/mol, takže M_HCl = 36,46 g/mol.
Látkové množstvo: n = 7,3/36,46 = 0,200 mol. Objem prepoč na dm³: 500 ml = 0,5 dm³. Molárna koncentrácia: c = 0,200/0,5 = 0,4 mol/dm³.
Tip: Vždy si najprv vypíš známe hodnoty a kontroluj jednotky pred výpočtom!
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
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Objemový zlomok a dôležité poznámky
Pri objemovom zlomku je výpočet priamočiaryy. Ak zmiešaš 75 ml etanolu s vodou a celkový objem je 250 ml, objemový zlomok je φ = 75/250 = 0,3, čo je 30 obj. %.
Najdôležitejšie tipy pre úspech:
- Kontroluj jednotky - hmotnosti musia byť v rovnakých jednotkách, objemy tiež
- Pri molárnej koncentrácii MUSÍ byť objem v dm³!
- Roztok ≠ rozpúšťadlo
Molárnu hmotnosť vždy počítaj z periodickej tabuľky pre konkrétnu látku. Niekedy budeš musieť prepočítavať medzi rôznymi typmi koncentrácií - to sa naučíš neskôr.
Pamätaj: Najčastejšia chyba sú zlé jednotky - vždy si ich skontroluj!
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
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.
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4.7/5
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 Knowunity AI. 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 Knowunity AI. 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