化学の計算で必ず出てくる「mol（モル）」って、実は超シンプルな考え方なんだ。原子や分子を1個ずつ数えるのは無理だから、決まった個数をまとめて「1セット」として扱うだけ。これを理解すれば化学の計算問題がグッと楽になるよ。
化学
理科
TOEIC
英語コミュニケーション
数学
国語
社会Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
77
•
Updated Mar 16, 2026
•
アボガドロ定数とモルの基本: 簡単な計算方法
1 / 5
物質量とアボガドロ定数の基本
**物質量（mol）**は、原子や分子の「個数の集団」を表す単位だ。鉛筆12本を「1ダース」と呼ぶのと同じ感覚で、1 mol = 6.02 × 10²³個の粒子の集まりを意味する。
アボガドロ定数（NA = 6.02 × 10²³ /mol）は絶対に覚えよう。これは1 molあたりの粒子数を表している。
原子量・分子量・式量はすべて単位がない相対的な数値。でもモル質量は「g/mol」という単位がついて、数値は原子量などと同じになる。例えば水（H₂O）の分子量は18だから、モル質量は18 g/molだ。
💡 重要ポイント：「mol」を中心に考えると、すべての変換がスムーズにできる！
質量・物質量・粒子数の三角関係
化学計算で一番大切なのは、**質量（g）、物質量（mol）、粒子の数（個）**の相互変換だ。すべての計算の中心に「mol」があると覚えておこう。
質量からmol：質量 ÷ モル質量 = mol molから質量：mol × モル質量 = 質量 molから粒子数：mol × アボガドロ定数 = 粒子数 粒子数からmol：粒子数 ÷ アボガドロ定数 = mol
まず「mol」を求めてから他の量に変換する、という流れで考えると分かりやすい。どの公式を使うか迷ったら、単位を見ながら計算すると間違えにくいよ。
💡 計算のコツ：単位も一緒に書きながら計算すると、どの操作をすべきか一目瞭然！
実践的な計算例
例題1：CO₂ 22gの物質量と分子数を求めてみよう。
まずCO₂の分子量を計算：C（12）+ O（16）× 2 = 44 だからモル質量は44 g/mol
物質量 = 22g ÷ 44 g/mol = 0.50 mol 分子数 = 0.50 mol × 6.0×10²³ /mol = 3.0×10²³個
例題2：1.2×10²⁴個の水分子の物質量と質量は？
物質量 = 1.2×10²⁴個 ÷ 6.0×10²³ /mol = 2.0 mol H₂Oの分子量は18だから、質量 = 2.0 mol × 18 g/mol = 36g
💡 計算の順序：必ず「mol」を経由して他の量に変換する習慣をつけよう！
テスト対策と重要ポイント
単位の使い分けに注意しよう。原子量・分子量・式量は無単位、モル質量には「g/mol」がつく。計算途中でも単位を書くクセをつけると、ミスが激減する。
分子数 vs 原子数の区別も超重要。メタン（CH₄）1molには分子が6.02×10²³個あるけど、原子は炭素1mol+水素4mol=合計5molの原子が含まれている。
有効数字は与えられた数値の中で最も桁数が少ないものに合わせるのが基本。22g（2桁）の計算結果なら、答えも2桁で表そう。
テストでよく出るのは、これらの変換を組み合わせた問題。焦らず「まずmolを求める」という基本に立ち返れば大丈夫だ。
💡 暗記必須：mol = g/ と 個数 = mol × NA の2つの式だけ覚えれば完璧！
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 化学
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
アボガドロ定数とモルの基本: 簡単な計算方法
化学の計算で必ず出てくる「mol（モル）」って、実は超シンプルな考え方なんだ。原子や分子を1個ずつ数えるのは無理だから、決まった個数をまとめて「1セット」として扱うだけ。これを理解すれば化学の計算問題がグッと楽になるよ。
物質量とアボガドロ定数の基本
**物質量（mol）**は、原子や分子の「個数の集団」を表す単位だ。鉛筆12本を「1ダース」と呼ぶのと同じ感覚で、1 mol = 6.02 × 10²³個の粒子の集まりを意味する。
アボガドロ定数（NA = 6.02 × 10²³ /mol）は絶対に覚えよう。これは1 molあたりの粒子数を表している。
原子量・分子量・式量はすべて単位がない相対的な数値。でもモル質量は「g/mol」という単位がついて、数値は原子量などと同じになる。例えば水（H₂O）の分子量は18だから、モル質量は18 g/molだ。
💡 重要ポイント：「mol」を中心に考えると、すべての変換がスムーズにできる！
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
質量・物質量・粒子数の三角関係
化学計算で一番大切なのは、**質量（g）、物質量（mol）、粒子の数（個）**の相互変換だ。すべての計算の中心に「mol」があると覚えておこう。
質量からmol：質量 ÷ モル質量 = mol molから質量：mol × モル質量 = 質量 molから粒子数：mol × アボガドロ定数 = 粒子数 粒子数からmol：粒子数 ÷ アボガドロ定数 = mol
まず「mol」を求めてから他の量に変換する、という流れで考えると分かりやすい。どの公式を使うか迷ったら、単位を見ながら計算すると間違えにくいよ。
💡 計算のコツ：単位も一緒に書きながら計算すると、どの操作をすべきか一目瞭然！
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
実践的な計算例
例題1：CO₂ 22gの物質量と分子数を求めてみよう。
まずCO₂の分子量を計算：C（12）+ O（16）× 2 = 44 だからモル質量は44 g/mol
物質量 = 22g ÷ 44 g/mol = 0.50 mol 分子数 = 0.50 mol × 6.0×10²³ /mol = 3.0×10²³個
例題2：1.2×10²⁴個の水分子の物質量と質量は？
物質量 = 1.2×10²⁴個 ÷ 6.0×10²³ /mol = 2.0 mol H₂Oの分子量は18だから、質量 = 2.0 mol × 18 g/mol = 36g
💡 計算の順序：必ず「mol」を経由して他の量に変換する習慣をつけよう！
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
テスト対策と重要ポイント
単位の使い分けに注意しよう。原子量・分子量・式量は無単位、モル質量には「g/mol」がつく。計算途中でも単位を書くクセをつけると、ミスが激減する。
分子数 vs 原子数の区別も超重要。メタン（CH₄）1molには分子が6.02×10²³個あるけど、原子は炭素1mol+水素4mol=合計5molの原子が含まれている。
有効数字は与えられた数値の中で最も桁数が少ないものに合わせるのが基本。22g（2桁）の計算結果なら、答えも2桁で表そう。
テストでよく出るのは、これらの変換を組み合わせた問題。焦らず「まずmolを求める」という基本に立ち返れば大丈夫だ。
💡 暗記必須：mol = g/ と 個数 = mol × NA の2つの式だけ覚えれば完璧！
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.
1
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 化学
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