Chemistry

Dec 8, 2025

192

4 pages

Learning About Moles: Easy Ways to Use Gas, Molar Mass, and Avogadro's Number!

Xiuyi 🦥 @xiuyiii

The mole concept is a fundamental principle in chemistry that relates the number of particles to measurable quantities... Show more

# Moles

3/1/22

Run: What is mole?

(νισμα) Σπολουs lostrida poradka

I. Mole a pile of particles (atoms Imolecules)

not larger enough | h

Solving Mole Problems

How to solve moles using volume of gases and mass involves understanding the relationships between moles, mass, and volume for gases. This page explores various methods to calculate moles.

Calculating Moles from Mass

To find the number of moles from a given mass

Determine the molar mass (gram formula mass, gfm) of the substance
Use the formula moles = given mass / molar mass

Example For 80g of Argon (Ar)

Molar mass of Ar = 40 g/mol

Moles = 80g / 40 g/mol = 2 moles

Calculating Particles from Moles

To find the number of particles

Molecules = (moles) x (Avogadro's number)
Atoms = (moles) x (Avogadro's number) x (number of atoms per molecule)

Example For 4.56g of NH₃

Molar mass of NH₃ = 17 g/mol

Moles = 4.56g / 17 g/mol ≈ 0.27 moles

Molecules = 0.27 x $6.02 x 10^23$ ≈ 1.63 x 10^23 molecules

Total atoms = 0.27 x $6.02 x 10^23$ x 4 ≈ 6.52 x 10^23 atoms

Highlight Understanding these relationships allows for easy conversion between mass, moles, and number of particles.

Solving Mole Problems with Gas Volume

This section focuses on how to calculate number of moles from volume of gas and introduces the concept of molar volume.

Molar Volume of Gases

At standard temperature and pressure (STP), one mole of any gas occupies 22.4 liters.

Definition Molar volume is the volume occupied by one mole of a gas at STP, which is 22.4 L.

Calculating Moles from Gas Volume

To find the number of moles from a given volume of gas at STP

moles = given volume / 22.4 L

Example For 10g of CO₂ gas at STP

Molar mass of CO₂ = 44 g/mol

Moles = 10g / 44 g/mol ≈ 0.23 moles

Volume = 0.23 moles x 22.4 L/mol ≈ 5.15 L

Calculating Volume from Moles

To find the volume of a gas from the number of moles at STP

Volume = (moles) x $22.4 L/mol$

Highlight The relationship between moles and volume for gases at STP allows for easy conversion between these quantities.

Quote "Volume of a gas is measured from the amount of empty spaces the gas particles occupy."

Understanding these relationships is crucial for solving problems involving gases in chemistry.

Mole Concept Practice Problems

This page provides practice problems to reinforce understanding of the mole concept and its applications.

Sample Problems

1 mole of Ar = 6.02 x 10^23 atoms = 40g
2 moles of Ar = 2 x $6.02 x 10^23$ atoms = 80g
1 mole of Fe = 6.02 x 10^23 atoms = 56g
1.7 moles of Fe = 1.7 x $6.02 x 10^23$ atoms ≈ 1.02 x 10^24 atoms
1 mole of Fe₂O₃ = 6.02 x 10^23 formula units = 160g

Example Calculating moles from mass For 22g of CO₂

Molar mass of CO₂ = 44 g/mol

Moles = 22g / 44 g/mol = 0.5 moles

Key Mole Equalities

There are three fundamental mole equalities

1 mole = 6.02 x 10^23 particles
1 mole = molar mass in grams
1 mole of gas = 22.4 L at STP

Highlight These equalities form the basis for solving most mole-related problems in chemistry.

Practice with these problems and equalities will help solidify understanding of the mole concept and its applications in various chemical calculations.

Understanding the Mole Concept

The mole is a fundamental unit in chemistry that bridges the microscopic and macroscopic worlds. It represents a specific number of particles, known as Avogadro's number.

Definition A mole is a pile of particles (atoms or molecules) containing 6.02 x 10^23 particles, known as Avogadro's number.

Vocabulary Molar mass is the mass of one mole of a substance, expressed in grams per mole $g/mol$ .

Key points about moles

One mole of any substance contains Avogadro's number of particles
The mass of one mole of an element or compound is its molar mass
For gases, one mole occupies 22.4 L at standard temperature and pressure (STP)

Example 1 mole of carbon (C) = 6.02 x 10^23 atoms of C = 12 g Example 1 mole of carbon dioxide (CO₂) = 6.02 x 10^23 molecules of CO₂ = 44 g

Understanding the relationship between moles, particles, and mass is crucial for solving chemical problems and performing calculations in chemistry.

Highlight The mole concept allows chemists to relate the number of particles to measurable quantities like mass and volume.

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.

Smart Tools NEW

Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines

Mock Exam

Quiz

Flashcards

Essay

Can't find what you're looking for? Explore other subjects.

Students love us — and so will you.

4.9/5

App Store

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

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

Stefan S

iOS user

Samantha Klich

Android user

Anna

iOS user

Thomas R

iOS user

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

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

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

Elisha

iOS user

Paul T

iOS user

Chemistry

•

192

•

Dec 8, 2025

•

4 pages

Learning About Moles: Easy Ways to Use Gas, Molar Mass, and Avogadro's Number!

Xiuyi 🦥

@xiuyiii

The mole concept is a fundamental principle in chemistry that relates the number of particles to measurable quantities like mass and volume. A mole contains Avogadro's number (6.02 x 10^23) of particles, whether atoms, molecules, or formula units. This... Show more

Sign up to see the contentIt's free!

Access to all documents

Improve your grades

Join milions of students

By signing up you accept Terms of Service and Privacy Policy

Solving Mole Problems

How to solve moles using volume of gases and mass involves understanding the relationships between moles, mass, and volume for gases. This page explores various methods to calculate moles.

Calculating Moles from Mass

To find the number of moles from a given mass:

Determine the molar mass (gram formula mass, gfm) of the substance
Use the formula: moles = given mass / molar mass

Example: For 80g of Argon (Ar)

Molar mass of Ar = 40 g/mol

Moles = 80g / 40 g/mol = 2 moles

Calculating Particles from Moles

To find the number of particles:

Molecules = (moles) x (Avogadro's number)
Atoms = (moles) x (Avogadro's number) x (number of atoms per molecule)

Example: For 4.56g of NH₃

Molar mass of NH₃ = 17 g/mol

Moles = 4.56g / 17 g/mol ≈ 0.27 moles

Molecules = 0.27 x $6.02 x 10^23$ ≈ 1.63 x 10^23 molecules

Total atoms = 0.27 x $6.02 x 10^23$ x 4 ≈ 6.52 x 10^23 atoms

Highlight: Understanding these relationships allows for easy conversion between mass, moles, and number of particles.

Sign up to see the contentIt's free!

Access to all documents

Improve your grades

Join milions of students

By signing up you accept Terms of Service and Privacy Policy

Solving Mole Problems with Gas Volume

This section focuses on how to calculate number of moles from volume of gas and introduces the concept of molar volume.

Molar Volume of Gases

At standard temperature and pressure (STP), one mole of any gas occupies 22.4 liters.

Definition: Molar volume is the volume occupied by one mole of a gas at STP, which is 22.4 L.

Calculating Moles from Gas Volume

To find the number of moles from a given volume of gas at STP:

moles = given volume / 22.4 L

Example: For 10g of CO₂ gas at STP

Molar mass of CO₂ = 44 g/mol

Moles = 10g / 44 g/mol ≈ 0.23 moles

Volume = 0.23 moles x 22.4 L/mol ≈ 5.15 L

Calculating Volume from Moles

To find the volume of a gas from the number of moles at STP:

Volume = (moles) x $22.4 L/mol$

Highlight: The relationship between moles and volume for gases at STP allows for easy conversion between these quantities.

Quote: "Volume of a gas is measured from the amount of empty spaces the gas particles occupy."

Understanding these relationships is crucial for solving problems involving gases in chemistry.

Sign up to see the contentIt's free!

Access to all documents

Improve your grades

Join milions of students

By signing up you accept Terms of Service and Privacy Policy

Mole Concept Practice Problems

This page provides practice problems to reinforce understanding of the mole concept and its applications.

Sample Problems

1 mole of Ar = 6.02 x 10^23 atoms = 40g
2 moles of Ar = 2 x $6.02 x 10^23$ atoms = 80g
1 mole of Fe = 6.02 x 10^23 atoms = 56g
1.7 moles of Fe = 1.7 x $6.02 x 10^23$ atoms ≈ 1.02 x 10^24 atoms
1 mole of Fe₂O₃ = 6.02 x 10^23 formula units = 160g

Example: Calculating moles from mass For 22g of CO₂:

Molar mass of CO₂ = 44 g/mol

Moles = 22g / 44 g/mol = 0.5 moles

Key Mole Equalities

There are three fundamental mole equalities:

1 mole = 6.02 x 10^23 particles
1 mole = molar mass in grams
1 mole of gas = 22.4 L at STP

Highlight: These equalities form the basis for solving most mole-related problems in chemistry.

Practice with these problems and equalities will help solidify understanding of the mole concept and its applications in various chemical calculations.

Sign up to see the contentIt's free!

Access to all documents

Improve your grades

Join milions of students

By signing up you accept Terms of Service and Privacy Policy

Understanding the Mole Concept

The mole is a fundamental unit in chemistry that bridges the microscopic and macroscopic worlds. It represents a specific number of particles, known as Avogadro's number.

Definition: A mole is a pile of particles (atoms or molecules) containing 6.02 x 10^23 particles, known as Avogadro's number.

Vocabulary: Molar mass is the mass of one mole of a substance, expressed in grams per mole $g/mol$ .

Key points about moles:

One mole of any substance contains Avogadro's number of particles
The mass of one mole of an element or compound is its molar mass
For gases, one mole occupies 22.4 L at standard temperature and pressure (STP)

Example: 1 mole of carbon (C) = 6.02 x 10^23 atoms of C = 12 g Example: 1 mole of carbon dioxide (CO₂) = 6.02 x 10^23 molecules of CO₂ = 44 g

Understanding the relationship between moles, particles, and mass is crucial for solving chemical problems and performing calculations in chemistry.

Highlight: The mole concept allows chemists to relate the number of particles to measurable quantities like mass and volume.