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Jan 26, 2026
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Understanding Matter and Mixtures: Chemistry Basics
Jocelyn Perez
@jocelynperez28
1 / 3
Introduction to Chemistry and Matter
Chemistry is the study of matter's behavior, composition, and transformations. While biology focuses on living organisms and physics examines energy and motion, chemistry specifically looks at what happens when substances change into other substances. This is why chemistry sits at the intersection of many sciences!
Matter is anything that has mass and takes up space. That smartphone in your pocket? Matter. The air you're breathing? Also matter. But empty space and light beams aren't matter because they lack mass or don't occupy volume.
The building blocks of matter are atoms, which are the smallest identifiable units of an element. When atoms with the same nuclear charge come together, they form an element like copper, oxygen, or gold. When different atoms bond together, they form molecules, and if those atoms are from different elements, they create compounds like water (H₂O) or table salt (NaCl).
💡 Quick Tip: Remember that all chemistry is essentially about changes in matter. If no substances are changing into other substances, it's probably not chemistry!
Classifications of Matter and Diatomic Elements
Matter can be organized into two main categories: pure substances and mixtures. Pure substances include elements (like gold or oxygen) and compounds (like water or salt). Elements can be further divided into atomic (single atoms like neon) or molecular (naturally bonded atoms like oxygen gas).
Compounds come in two main types: ionic compounds (formed between metals and nonmetals, like table salt) and molecular compounds (formed between nonmetals, like water). The difference matters because it affects how they behave in reactions!
Seven elements naturally exist as pairs of atoms called diatomic elements. Remember them with this phrase: Have No Fear Of Ice Cold Beer (H₂, N₂, F₂, O₂, I₂, Cl₂, Br₂). Notice that most elements ending in "gen" are diatomic - a helpful memory trick!
🔑 Remember: When writing chemical formulas, diatomic elements must be written with subscript 2 when they're in their elemental form - it's O₂, not just O!
Mixtures and Physical vs. Chemical Changes
Mixtures combine multiple substances that aren't chemically bonded. They can be homogeneous (uniform throughout, like salt completely dissolved in water) or heterogeneous .
When matter changes, it undergoes either physical or chemical changes. Physical changes don't create new substances - they just alter appearance, state, or form. Think melting ice or dissolving sugar. Physical properties include color, boiling point, density, and electrical conductivity.
Chemical changes transform substances into entirely different ones with new properties. Examples include rusting metal, burning wood, or digesting food. You might see color changes, gas bubbles, or new solids forming during chemical reactions.
Matter exists in different states: solid (definite shape and volume), liquid (indefinite shape but definite volume), or gas (indefinite shape and volume). Transitions between states have specific names: melting (solid→liquid), freezing (liquid→solid), boiling/evaporation (liquid→gas), condensation (gas→liquid), sublimation (solid→gas), and deposition (gas→solid).
🧪 Science Fact: Only two elements are liquid at room temperature - mercury and bromine. All metals conduct electricity well, while non-metals generally don'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
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
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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
homepage/newPositiveReviewText6
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
homepage/newPositiveReviewText6
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
Understanding Matter and Mixtures: Chemistry Basics
Jocelyn Perez
@jocelynperez28
Chemistry explores the fascinating world of matter and how substances transform into other substances. This fundamental science connects to everything from the air we breathe to the technology in our phones. Let's break down the basics of chemistry and matter... Show more
Introduction to Chemistry and Matter
Chemistry is the study of matter's behavior, composition, and transformations. While biology focuses on living organisms and physics examines energy and motion, chemistry specifically looks at what happens when substances change into other substances. This is why chemistry sits at the intersection of many sciences!
Matter is anything that has mass and takes up space. That smartphone in your pocket? Matter. The air you're breathing? Also matter. But empty space and light beams aren't matter because they lack mass or don't occupy volume.
The building blocks of matter are atoms, which are the smallest identifiable units of an element. When atoms with the same nuclear charge come together, they form an element like copper, oxygen, or gold. When different atoms bond together, they form molecules, and if those atoms are from different elements, they create compounds like water (H₂O) or table salt (NaCl).
💡 Quick Tip: Remember that all chemistry is essentially about changes in matter. If no substances are changing into other substances, it's probably not chemistry!
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Classifications of Matter and Diatomic Elements
Matter can be organized into two main categories: pure substances and mixtures. Pure substances include elements (like gold or oxygen) and compounds (like water or salt). Elements can be further divided into atomic (single atoms like neon) or molecular (naturally bonded atoms like oxygen gas).
Compounds come in two main types: ionic compounds (formed between metals and nonmetals, like table salt) and molecular compounds (formed between nonmetals, like water). The difference matters because it affects how they behave in reactions!
Seven elements naturally exist as pairs of atoms called diatomic elements. Remember them with this phrase: Have No Fear Of Ice Cold Beer (H₂, N₂, F₂, O₂, I₂, Cl₂, Br₂). Notice that most elements ending in "gen" are diatomic - a helpful memory trick!
🔑 Remember: When writing chemical formulas, diatomic elements must be written with subscript 2 when they're in their elemental form - it's O₂, not just O!
Sign up to see the contentIt's free!
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Join milions of students
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Mixtures and Physical vs. Chemical Changes
Mixtures combine multiple substances that aren't chemically bonded. They can be homogeneous (uniform throughout, like salt completely dissolved in water) or heterogeneous .
When matter changes, it undergoes either physical or chemical changes. Physical changes don't create new substances - they just alter appearance, state, or form. Think melting ice or dissolving sugar. Physical properties include color, boiling point, density, and electrical conductivity.
Chemical changes transform substances into entirely different ones with new properties. Examples include rusting metal, burning wood, or digesting food. You might see color changes, gas bubbles, or new solids forming during chemical reactions.
Matter exists in different states: solid (definite shape and volume), liquid (indefinite shape but definite volume), or gas (indefinite shape and volume). Transitions between states have specific names: melting (solid→liquid), freezing (liquid→solid), boiling/evaporation (liquid→gas), condensation (gas→liquid), sublimation (solid→gas), and deposition (gas→solid).
🧪 Science Fact: Only two elements are liquid at room temperature - mercury and bromine. All metals conduct electricity well, while non-metals generally don't!
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.
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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
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
homepage/newPositiveReviewText6
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
homepage/newPositiveReviewText6
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