Biology
Chemistry
AP Chemistry
English
AP English Literature
Biology
Dec 1, 2025
82
5 pages
Anoushka Jena @anoushka.jena
Chemistry is the foundation of all life processes! This chapter explores the building blocks of matter, how atoms... Show more
Matter is anything that takes up space and has mass - including you! The basic units of matter are elements, substances that can't be broken down further by normal chemical means. Six elements make up 99% of your body Oxygen, Carbon, Hydrogen, Nitrogen, Calcium, and Phosphorus.
Atoms are the smallest units of elements, composed of three key subatomic particles. Protons (positively charged) and neutrons (no charge) are located in the nucleus, while electrons (negatively charged) orbit around it. The number of protons determines an element's identity - this is called the atomic number. The mass number is the total protons plus neutrons.
Isotopes are atoms of the same element with different numbers of neutrons. While they behave almost identically chemically, some isotopes have special properties used in medicine and research.
💡 Think of atoms like tiny solar systems - the nucleus is the sun, and electrons are planets orbiting around it. The difference is that electrons move in specific energy levels, not circular paths!
The outer energy level of an atom (the valence shell) determines how it will interact with other atoms. Atoms are most stable when their outer shells are full - typically with 8 electrons (except the first level, which needs 2). Atoms with incomplete valence shells react readily with others to achieve stability.
When atoms bond, they share or transfer electrons. In covalent bonds, atoms share electrons between them, creating molecules. In ionic bonds, atoms actually transfer electrons completely, creating charged particles called ions.
The difference between polar and nonpolar covalent bonds comes down to how evenly electrons are shared
Understanding these bonds helps explain why some substances dissolve in water while others don't. Water molecules form hydrogen bonds between each other, which gives water many of its life-supporting properties.
💡 Think of chemical bonds like relationships - in covalent bonds, atoms share electrons like roommates sharing a TV, while in ionic bonds, one atom gives electrons to another like giving a gift!
Ions form when atoms gain or lose electrons, creating particles with a positive or negative charge. For example, sodium (Na) loses an electron to become Na⁺, while chlorine (Cl) gains an electron to become Cl⁻. Together, they form sodium chloride (NaCl) - table salt!
Ionic bonds are strong in dry solids but weaken when placed in water. This explains why salt crystals are hard but dissolve easily in water. Water molecules surround the ions, pulling them apart from each other.
Chemical reactions occur when existing bonds break and new ones form. During reactions, atoms rearrange themselves, but the total number of each type of atom remains the same. For example, when hydrogen (H₂) reacts with oxygen (O₂), water (H₂O) forms 2H₂ + O₂ → 2H₂O.
Hydrogen bonds are special attractions that form between molecules (not within them). Though weaker than covalent or ionic bonds, they're crucial for life. These bonds give water its unique properties and help shape important biological molecules like DNA.
🔍 Chemical reactions power everything in your body! Every time you eat food, breathe, or move a muscle, countless chemical reactions are taking place, breaking and forming bonds to release energy.
Water is often called the "universal solvent" because it can dissolve so many substances. This is due to its polar nature - the oxygen atom pulls electrons more strongly than hydrogen, creating slightly negative and positive regions in the molecule.
A solution forms when substances dissolve in a liquid. The dissolving liquid is the solvent (usually water in living systems), and the dissolved substance is the solute. When water is the solvent, we call it an aqueous solution - and most reactions in your body occur in these solutions!
Water molecules form hydrogen bonds with each other, giving water unique properties that support life
These properties make water the perfect environment for life's chemical reactions to occur.
💦 Without water's special properties, life as we know it couldn't exist. That's why scientists get so excited when they find water on other planets - it might mean the possibility of life!
The pH scale measures how acidic or basic (alkaline) a solution is, ranging from 0-14. Acids donate hydrogen ions (H⁺) to solutions, while bases reduce hydrogen ion concentration. The lower the pH number, the more acidic the solution.
Here's what makes pH interesting each full step on the pH scale represents a 10-fold difference in hydrogen ion concentration. A solution with pH 3 has 10 times more hydrogen ions than one with pH 4!
Most living cells require a pH between 7.0-7.4 to function properly. Even small changes can damage proteins and disrupt cellular processes. That's why your body has buffers - special molecules that resist pH changes by absorbing or releasing hydrogen ions as needed.
Buffers are critical in living systems because they maintain the stable internal environment cells need. Your blood contains several buffer systems that keep its pH steady at around 7.4, even when acidic or basic substances enter your bloodstream.
🧪 Next time you drink a soda (pH ~2.5), remember your body is working hard to neutralize that acidity! Without buffers, even one soda could potentially disrupt your blood pH enough to cause serious problems.
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.
You can download the app in the Google Play Store and in the Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
4
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
8.1-8.6
BiologyNotes describing carbohydrates, what they are, and the role they play in biology.
Biologymonosaccharides, disaccharides, polysaccharides, glycosidic linkage, phospholipids, ester linkage
BiologyNotes on how cell transport works
BiologyNotes and key concepts on Water and Life
BiologyExplore the essential characteristics of living organisms, including movement, respiration, sensitivity, growth, reproduction, excretion, and nutrition. This summary provides key definitions and a mnemonic to help you remember these vital biological processes. Ideal for biology students seeking to understand the fundamental traits that define life.
BiologyApp Store
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 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 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 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 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
Anoushka Jena
@anoushka.jena
Chemistry is the foundation of all life processes! This chapter explores the building blocks of matter, how atoms interact, and why these interactions are crucial for living organisms. Understanding these basic chemical principles will help you make sense of everything... Show more
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Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Matter is anything that takes up space and has mass - including you! The basic units of matter are elements, substances that can't be broken down further by normal chemical means. Six elements make up 99% of your body: Oxygen, Carbon, Hydrogen, Nitrogen, Calcium, and Phosphorus.
Atoms are the smallest units of elements, composed of three key subatomic particles. Protons (positively charged) and neutrons (no charge) are located in the nucleus, while electrons (negatively charged) orbit around it. The number of protons determines an element's identity - this is called the atomic number. The mass number is the total protons plus neutrons.
Isotopes are atoms of the same element with different numbers of neutrons. While they behave almost identically chemically, some isotopes have special properties used in medicine and research.
💡 Think of atoms like tiny solar systems - the nucleus is the sun, and electrons are planets orbiting around it. The difference is that electrons move in specific energy levels, not circular paths!
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Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
The outer energy level of an atom (the valence shell) determines how it will interact with other atoms. Atoms are most stable when their outer shells are full - typically with 8 electrons (except the first level, which needs 2). Atoms with incomplete valence shells react readily with others to achieve stability.
When atoms bond, they share or transfer electrons. In covalent bonds, atoms share electrons between them, creating molecules. In ionic bonds, atoms actually transfer electrons completely, creating charged particles called ions.
The difference between polar and nonpolar covalent bonds comes down to how evenly electrons are shared:
Understanding these bonds helps explain why some substances dissolve in water while others don't. Water molecules form hydrogen bonds between each other, which gives water many of its life-supporting properties.
💡 Think of chemical bonds like relationships - in covalent bonds, atoms share electrons like roommates sharing a TV, while in ionic bonds, one atom gives electrons to another like giving a gift!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Ions form when atoms gain or lose electrons, creating particles with a positive or negative charge. For example, sodium (Na) loses an electron to become Na⁺, while chlorine (Cl) gains an electron to become Cl⁻. Together, they form sodium chloride (NaCl) - table salt!
Ionic bonds are strong in dry solids but weaken when placed in water. This explains why salt crystals are hard but dissolve easily in water. Water molecules surround the ions, pulling them apart from each other.
Chemical reactions occur when existing bonds break and new ones form. During reactions, atoms rearrange themselves, but the total number of each type of atom remains the same. For example, when hydrogen (H₂) reacts with oxygen (O₂), water (H₂O) forms: 2H₂ + O₂ → 2H₂O.
Hydrogen bonds are special attractions that form between molecules (not within them). Though weaker than covalent or ionic bonds, they're crucial for life. These bonds give water its unique properties and help shape important biological molecules like DNA.
🔍 Chemical reactions power everything in your body! Every time you eat food, breathe, or move a muscle, countless chemical reactions are taking place, breaking and forming bonds to release energy.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Water is often called the "universal solvent" because it can dissolve so many substances. This is due to its polar nature - the oxygen atom pulls electrons more strongly than hydrogen, creating slightly negative and positive regions in the molecule.
A solution forms when substances dissolve in a liquid. The dissolving liquid is the solvent (usually water in living systems), and the dissolved substance is the solute. When water is the solvent, we call it an aqueous solution - and most reactions in your body occur in these solutions!
Water molecules form hydrogen bonds with each other, giving water unique properties that support life:
These properties make water the perfect environment for life's chemical reactions to occur.
💦 Without water's special properties, life as we know it couldn't exist. That's why scientists get so excited when they find water on other planets - it might mean the possibility of life!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
The pH scale measures how acidic or basic (alkaline) a solution is, ranging from 0-14. Acids donate hydrogen ions (H⁺) to solutions, while bases reduce hydrogen ion concentration. The lower the pH number, the more acidic the solution.
Here's what makes pH interesting: each full step on the pH scale represents a 10-fold difference in hydrogen ion concentration. A solution with pH 3 has 10 times more hydrogen ions than one with pH 4!
Most living cells require a pH between 7.0-7.4 to function properly. Even small changes can damage proteins and disrupt cellular processes. That's why your body has buffers - special molecules that resist pH changes by absorbing or releasing hydrogen ions as needed.
Buffers are critical in living systems because they maintain the stable internal environment cells need. Your blood contains several buffer systems that keep its pH steady at around 7.4, even when acidic or basic substances enter your bloodstream.
🧪 Next time you drink a soda (pH ~2.5), remember your body is working hard to neutralize that acidity! Without buffers, even one soda could potentially disrupt your blood pH enough to cause serious problems.
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.
You can download the app in the Google Play Store and in the Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
4
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
8.1-8.6
BiologyNotes describing carbohydrates, what they are, and the role they play in biology.
Biologymonosaccharides, disaccharides, polysaccharides, glycosidic linkage, phospholipids, ester linkage
BiologyNotes on how cell transport works
BiologyNotes and key concepts on Water and Life
BiologyExplore the essential characteristics of living organisms, including movement, respiration, sensitivity, growth, reproduction, excretion, and nutrition. This summary provides key definitions and a mnemonic to help you remember these vital biological processes. Ideal for biology students seeking to understand the fundamental traits that define life.
BiologyApp Store
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 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 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 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 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
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