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Home » Class 11 » Chemistry » Some basic concepts of chemistry » Mole concept

Mole concept

Last Updated on March 20, 2019 By Mrs Shilpi Nagpal 19 Comments

Mole Concept – Some Basic Concepts of Chemistry – Class 11     

One gram atom of any element contains the same number of atoms and one gram molecule of any substance contains the same number of molecules.

The value was found to be 6.022137 × 1023

The value generally used is 6.022 × 1023 .

This is called Avogadro’s number or Avogadro’s constant (NA)

Avogadro’s number may be defined as the number of atoms present in one gram atom of the element or the number of molecules present in one gram molecule of the substance.

A mole is a chemist unit of counting particles such as atom, molecules, ions, electrons, protons which represent a value of 6.022 × 1023 

A mole of hydrogen atom means 6.022 × 1023  atoms of hydrogen whereas a mole of hydrogen molecule means 6.022 × 1023  molecules of hydrogen or 2 × 6.022 × 1023 atoms of hydrogen .

A mole of oxygen molecule means 6.022 × 1023  molecules of oxygen or 2 × 6.022 × 1023 atoms of oxygen.

A mole is defined as that amount of substance which has mass equal to gram atomic mass if the substance is atomic or gram molecular mass if the substance is molecular.

1 mole of carbon atoms =12 grams

1 mole of sodium atoms = 23 grams

1 mole of Oxygen atom = 16 grams

1 mole of Oxygen molecule = 32 grams

1 mole of water molecule = 18 grams

1 mole of carbon dioxide molecule = 44 grams

A mole is defined as that amount of substance which contains Avogadro’s number of atoms if the substance is atomic or Avogadro’s number of molecules if the substance is molecular.

1 mole of carbon atoms = 6.022 ×1023 atoms of carbon.

1 mole of sodium atom = 6.022 ×1023 atoms of sodium

1 mole of Oxygen atom =6.022 ×1023 atoms of oxygen

1 mole of Oxygen molecule =6.022 ×1023  molecules of oxygen

1 mole of water =6.022 ×1023  molecules of water

In case of gases, a mole is defined as that amount of the gas which has a volume of 22.4 litres at STP.

1 mole of Oxygen gas = 22.4 litres of oxygen at STP

one mole of carbon dioxide gas = 22.4 litres of carbon dioxide at STP

A mole of an ionic compound is defined as that amount of the substance which has mass equal to gram formula mass or which contains Avogadro’s number of formula unit.

1 mole of NaCl = 58.5 grams of NaCl

1 mole of NaCl =6.022 ×1023 formula units of NaCl = 6.022 ×1023 Na+ ion and 6.022 ×1023   Cl– ion.

Importance of Avogadro’s number and mole concept

  1. In the calculation of actual mass of a single atom of an element or a single molecule of a substance.
  2. In the calculation of the number of atoms or molecules in a given mass of the element of the compound.
  3. In the calculation of the number of molecules present in a given volume of the gas under given conditions.
  4. In the calculation of the size of the individual atoms and molecules assuming them to the spherical.
  5. In the calculation of actual masses of 1 amu or 1 u.

1 amu = 1.6606 × 10-24 g

1 amu = 1.6606 × 10-27 kg

Filed Under: Chemistry, Class 11, Some basic concepts of chemistry Tagged With: avogadro's number, Importance of Avogadro's number, mole

About Mrs Shilpi Nagpal

Author of this website, Mrs Shilpi Nagpal is MSc (Hons, Chemistry) and BSc (Hons, Chemistry) from Delhi University, B.Ed (I. P. University) and has many years of experience in teaching. She has started this educational website with the mindset of spreading Free Education to everyone.

Reader Interactions

Comments

  1. Ankit singh says

    July 21, 2018 at 8:40 am

    it’s the best concept of chemistry about mole, thanks!

    Reply
  2. ANSI roy says

    November 23, 2018 at 1:14 pm

    It really helped me alot it’s a great explanation

    Reply
  3. Anushka Raj says

    December 14, 2018 at 12:13 am

    It’s very useful for me…….. thanks

    Reply
  4. Armaan says

    January 5, 2019 at 7:11 pm

    It’s really very useful for me ……. thank you very much

    Reply
  5. Vishal khera says

    February 20, 2019 at 7:47 pm

    It is very helpful and help me lots

    Reply
  6. anshika says

    April 30, 2019 at 11:51 pm

    Thanx it is really helped me to understand mole concept of class 11

    Reply
  7. Prashant says

    May 10, 2019 at 11:25 pm

    Thanks it is very good and helpful for me

    Reply
  8. suruj saikia says

    May 11, 2019 at 12:42 am

    It’s quite helpful for me so clear and easily digestible.expecting more guidance in future Regards

    Reply
  9. Jyoti manhas says

    June 22, 2019 at 6:48 pm

    Thanks a lot it’s helps me to understand mole concept in best way

    Reply
  10. Shoib akhtar says

    September 6, 2019 at 6:34 pm

    Can you take a class for me plz

    Reply
  11. Fairy_Queen says

    September 10, 2019 at 4:14 pm

    Thanks for the material. It was really helpful for a better understanding of the concept.
    It would be wonderful if other definitions and formulas were also included.
    Thanks a lot.

    Reply
  12. Satbhisha Nayak says

    April 8, 2020 at 4:20 pm

    It was really helpful
    Thanks.

    Reply
  13. Helie says

    April 9, 2020 at 1:35 pm

    this content is very helpful. Thank you

    Reply
    • pragna says

      September 9, 2020 at 12:42 pm

      The matter is very good and helpful. I understood it very well

      Reply
  14. Kuldeep skukla says

    May 27, 2020 at 11:25 pm

    This is very help full now i really understand mole concept…thank you……

    Reply
  15. Arunendu Biswas says

    July 8, 2020 at 6:21 am

    This is really helpful for me.
    thank you very much…

    Reply
  16. Anchal says

    September 22, 2020 at 4:13 pm

    Very nice it is soo helpful

    Reply
  17. keshav dangol says

    October 16, 2020 at 8:46 am

    thank you for good presentation about mole concept

    Reply
  18. Nancy says

    November 9, 2020 at 3:26 pm

    very nyc ,… usefull

    Reply

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