Zakon o ohranitvi mase je eno najbolj pomembnih pravil v... Show more
Kemija
Matematika
Angleščina
GeografijaSign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
7
•
Updated Apr 15, 2026
•
Kaj je Zakon o Ohranitvi Mase?
1 / 6
Osnove zakona o ohranitvi mase
Predstavljaj si kemijsko reakcijo kot preurejanje kock Lego. Če imaš na začetku 50 gramov kock in iz njih zgradiš hišo, bo hiša še vedno tehtala 50 gramov. V kemiji je enako - atomi se samo preuredijo, ne izginejo!
Reaktanti so snovi, s katerimi začneš reakcijo (kot razmetane kocke). Produkti so snovi, ki nastanejo (kot zgrajena hiša). Zakon o ohranitvi mase pravi, da je masa reaktantov vedno enaka masi produktov.
To pravilo je odkril Antoine Lavoisier, ki mu pravimo "oče sodobne kemije". Dobro si zapomni to ime za test!
💡 Zapomniti si moraš: Snov se med reakcijo samo preuredi, nikoli ne izgine ali nastane iz nič.
Kako deluje v praksi
Ko gledaš kemijsko enačbo, moraš preveriti, ali je na obeh straneh enako število atomov vsakega elementa. Vzemi nastanek vode: 2H₂ + O₂ → 2H₂O.
Na levi strani imaš 4 atome vodika in 2 atoma kisika. Na desni strani prav tako 4 atome vodika (v dveh molekulah vode) in 2 atoma kisika. Ker se število atomov ne spremeni, se tudi masa ne.
Če bi imel 4 g vodika in 32 g kisika, bi nastalo natanko 36 g vode. Formula je preprosta: m(reaktanti) = m(produkti).
💡 Hitri trik: Vedno preštej atome na obeh straneh enačbe - če se ujemajo, se bo ujemala tudi masa!
Reševanje nalog korak za korak
Pri računskih primerih sledi vedno istemu postopku. Če 56 g železa reagira z 24 g kisika in nastane rja, koliko rje nastane?
Najprej zapiši podatke: reaktanta sta železo (56 g) in kisik (24 g), produkt je rja. Uporabi zakon ohranitvi mase: masa reaktantov = masa produktov.
Preprosto sešteješ: 56 g + 24 g = 80 g. Torej nastane 80 g rje. Če imaš obratno nalogo in poznaš maso enega produkta, preprosto odšteješ od skupne mase reaktantov.
💡 Za teste: Vedno preveri, ali si upošteval vse snovi - tudi tiste, ki jih nisi eksplicitno omenil!
Pozor na past - odprti in zaprti sistemi
Največja napaka pri ohranitvi mase je, da pozabiš na plinske snovi! V odprtem sistemu (npr. odprta čaša) lahko plini uidejo ali pridejo iz zraka.
Če meša kis in sodo bikarbono v odprti čaši, bo masa na koncu manjša, ker ogljikov dioksid uide. Pri gorenju lesa se masa navidezno poveča, ker les reagira s kisikom iz zraka, ki ga nisi stehtал na začetku.
V zaprtem sistemu (zaprta posoda) masa ostane vedno enaka, ker nobena snov ne more uiti. Če bi reakcijo kisa in sode naredil v zaprti plastenki, bi se ta samo napihnila, ampak skupna masa bi ostala enaka.
💡 Ključno vprašanje: Ali lahko katera koli snov uide iz sistema ali pride vanj? To ti pove, zakaj se masa navidezno spremeni.
We thought you’d never ask...
What is the Knowunity AI companion?
Our AI companion is specifically built for the needs of students. Based on the millions of content pieces we have on the platform we can provide truly meaningful and relevant answers to students. But its not only about answers, the companion is even more about guiding students through their daily learning challenges, with personalised study plans, quizzes or content pieces in the chat and 100% personalisation based on the students skills and developments.
Where can I download the Knowunity app?
You can download the app in the Google Play Store and in the 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.
Most popular content in Kemija
Most popular content
Can't find what you're looking for? Explore other subjects.
Students love us — and so will you.
4.6/5
App Store
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
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
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
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
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 app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
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
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
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
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
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 app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
Paul T
iOS user
Kaj je Zakon o Ohranitvi Mase?
Zakon o ohranitvi mase je eno najbolj pomembnih pravil v kemiji, ki ga boš potreboval pri vseh kemijskih reakcijah. To pravilo ti pove, da se snovi med kemijsko reakcijo ne morejo kar pojaviti iz nič ali popolnoma izginiti - samo... Show more
Osnove zakona o ohranitvi mase
Predstavljaj si kemijsko reakcijo kot preurejanje kock Lego. Če imaš na začetku 50 gramov kock in iz njih zgradiš hišo, bo hiša še vedno tehtala 50 gramov. V kemiji je enako - atomi se samo preuredijo, ne izginejo!
Reaktanti so snovi, s katerimi začneš reakcijo (kot razmetane kocke). Produkti so snovi, ki nastanejo (kot zgrajena hiša). Zakon o ohranitvi mase pravi, da je masa reaktantov vedno enaka masi produktov.
To pravilo je odkril Antoine Lavoisier, ki mu pravimo "oče sodobne kemije". Dobro si zapomni to ime za test!
💡 Zapomniti si moraš: Snov se med reakcijo samo preuredi, nikoli ne izgine ali nastane iz nič.
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
Kako deluje v praksi
Ko gledaš kemijsko enačbo, moraš preveriti, ali je na obeh straneh enako število atomov vsakega elementa. Vzemi nastanek vode: 2H₂ + O₂ → 2H₂O.
Na levi strani imaš 4 atome vodika in 2 atoma kisika. Na desni strani prav tako 4 atome vodika (v dveh molekulah vode) in 2 atoma kisika. Ker se število atomov ne spremeni, se tudi masa ne.
Če bi imel 4 g vodika in 32 g kisika, bi nastalo natanko 36 g vode. Formula je preprosta: m(reaktanti) = m(produkti).
💡 Hitri trik: Vedno preštej atome na obeh straneh enačbe - če se ujemajo, se bo ujemala tudi masa!
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
Reševanje nalog korak za korak
Pri računskih primerih sledi vedno istemu postopku. Če 56 g železa reagira z 24 g kisika in nastane rja, koliko rje nastane?
Najprej zapiši podatke: reaktanta sta železo (56 g) in kisik (24 g), produkt je rja. Uporabi zakon ohranitvi mase: masa reaktantov = masa produktov.
Preprosto sešteješ: 56 g + 24 g = 80 g. Torej nastane 80 g rje. Če imaš obratno nalogo in poznaš maso enega produkta, preprosto odšteješ od skupne mase reaktantov.
💡 Za teste: Vedno preveri, ali si upošteval vse snovi - tudi tiste, ki jih nisi eksplicitno omenil!
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
Pozor na past - odprti in zaprti sistemi
Največja napaka pri ohranitvi mase je, da pozabiš na plinske snovi! V odprtem sistemu (npr. odprta čaša) lahko plini uidejo ali pridejo iz zraka.
Če meša kis in sodo bikarbono v odprti čaši, bo masa na koncu manjša, ker ogljikov dioksid uide. Pri gorenju lesa se masa navidezno poveča, ker les reagira s kisikom iz zraka, ki ga nisi stehtал na začetku.
V zaprtem sistemu (zaprta posoda) masa ostane vedno enaka, ker nobena snov ne more uiti. Če bi reakcijo kisa in sode naredil v zaprti plastenki, bi se ta samo napihnila, ampak skupna masa bi ostala enaka.
💡 Ključno vprašanje: Ali lahko katera koli snov uide iz sistema ali pride vanj? To ti pove, zakaj se masa navidezno spremeni.
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 specifically built for the needs of students. Based on the millions of content pieces we have on the platform we can provide truly meaningful and relevant answers to students. But its not only about answers, the companion is even more about guiding students through their daily learning challenges, with personalised study plans, quizzes or content pieces in the chat and 100% personalisation based on the students skills and developments.
Where can I download the Knowunity app?
You can download the app in the Google Play Store and in the 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.
0
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Practice Test ✓ Essay Outlines
Practice Test
Quiz
Flashcards
Essay
Most popular content in Kemija
Most popular content
Can't find what you're looking for? Explore other subjects.
Students love us — and so will you.
4.6/5
App Store
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
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
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
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
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 app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
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
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
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
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
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 app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
Paul T
iOS user