Thursday, 12 September 2019

CHAPTER 13:GAS LAW & KINETIC THEORY subtopic : Degree of Freedom


                                   

                                         watch this video   https://youtu.be/GHMHa5E1kGk

74 comments:

  1. also can watch these videos :

    Diana s3t5
    https://drive.google.com/open?id=12HfJYyEvdSJkNtkLsIcA_IsDZvunbJz4
    https://drive.google.com/open?id=12axj04hJi_Z4uqH7BZzRx-yRH8VLM2C1

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  2. Replies
    1. if have any problem about this topic,just ask here..a.s.a.p,don't let them make you confuse and becomes crazy.ehehehe.PHYSICS is a simple things..just understand the concept

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    2. Sachini S3T5
      Thank you madam.Just to confirm madam, we don't have to know about the vibration of atoms for the degree of freedom at different temperatures as we can ignore it right?

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    3. We neglect the vibration because the molecules have less vibration at low temperature.

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    4. The discussion is about ideal gas not real gas.we just focused on parameters involved based on ideal gass assumption..

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    5. vibration of molecules :
      1)at low temperatures - no vibration in gasses
      2) we can consider molecules as atoms on the spring.They are bound by chemical bond but close to equilibrium. This bond behaves very much like a spring. we can initiate vibration by collision with another energetic molecule, but the vibration itself is like a vibration of the spring which it is internal property of the spring. it seem we would exerted force to make the vibration will go on. So for molecules, which have minimum energy so the vibration will not start.
      that is why we do not consider vibration as degree of freedom

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    6. but it could be different when the temperature is extremely high

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  3. Diana S3T5
    Thank you madam saya faham dah chap ni

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  4. Prissha S3T5
    Thank you madam.Able to understand well

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  5. nabilah S3T5
    bole madam share soalan2 yang berkaitan dgn degree of freedom?

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  6. Intan S3T5
    Thank you madam for sharing info about this chapter.

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  7. This comment has been removed by the author.

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  8. Hanis S3T5
    Thank you madam..boleh x madam share contoh2 soalan yg slalu ditanya dlm exam utk tajuk ini.😄

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  9. Syakinah S3T5
    Tq madam i am able to understand this subtopic better after watching the video

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  10. Syazleen S3T5
    Thank you madam for sharing this video

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  11. thank you madam. good teaching skills and easy to understand.

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  12. Athirah S3T5
    Thank you for the info madam. Able to understand better after watching the video

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  13. Azera S3T5
    Thank you madam, through this video i can understand this subtopic well ..

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  14. Mun S3T5.
    Tq madam. Tapi kan, boleh ke guna formula K=(1/2)mv^2 instead of K=(f/2)kT for translational??????


    Uhukss..confuse

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    Replies
    1. Actually can use both equations..but in this chapter,we focused on the effect on the kinetic energy due to Temperature and degree of freedom..

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  15. Syuhada S3T5
    Thank you Madam.. This video is very helpful for me to understand this subtopic better..

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  16. Shanthiraa S3at5
    Thank you madam..i can understand well after watching the video

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  17. Ching Jia Ying S3T5

    Thank you madam, I've understand more on this topic~

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    Replies
    1. very good. Then check your understanding by doing exercise.click TEST SEMESTER 1 CHP 13..now its time to consolidate your understanding about this concept

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  18. fatah S3T5
    im little bit confused wheter we nees to change all the unit to SI unit???

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    Replies
    1. mathematical operation needs them in the same unit. if the question didn't mention about SI unit, so you can use both either SI unit or equivalent unit. but my suggestion is make sure all physical quantities are in SI unit to avoid any conflict in your calculation.

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  19. This comment has been removed by a blog administrator.

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  20. Thanks madam for sharing this topic 😊 alia F3T3

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  21. Keywords for assumption of ideal gas:
    1)build up
    2)motion
    3)volume
    4)collision
    5)type of collision
    6)force
    7)time
    8)gravity

    Explain these breifly...i'm waiting for your answer😍😍😍

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    Replies
    1. 1) all gases are made up identical atoms or molecules
      2) all atoms or molecules move randomly and haphazardly
      3) the volume of atoms is negligible compares with the volume occupied by gas

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    2. 4) the inter molecular forces are negligible except during collision
      5)inter molecular or atomic collision are elastic
      6) the duration of a collision is negligible compares with the time spent travelling between collision
      7) atoms and molecules move with constant speed between collisions. Gravity has no effect on molecular motion

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    3. Perfect!!!very good😍😍😍everyone,make sure you could able to know this before you sleep tonight,okes😜this content should be as multiple choice question in PSPM..compulsory to state all these things okes😍

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  22. What is the difference between KINETIC ENERGY and TRANSLATIONAL KINETIC ENERGY for gases?

    Reminder:introduce yourself e.g name and cls

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    Replies
    1. Sachini S3T5
      Hi madam, if I'm not wrong kinetic energy is energy possessed due to the motion of an object and occurs randomly but translational kinetic energy takes count the three direction of translational motion..

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    2. syafiqah S2T1

      kinetic energy is the energy possessed by a body because of its motion while trans kinetic energy is the energy depends on motion through space.. is it true madam?

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  23. Aiman f3t3

    Kinetic energy is the energy of an object that has motion while translational kinetic energy is the energy due to motion from one location to another.

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  24. Conclusion:
    1)Average kinetic energy-must consider all degree of freedom (translational+rotational)-different for all type of gases

    2)translational kinetic energy-must consider degree of freedom for translational only(f=3 same for all type of gases)

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  25. What is the difference between average kinetic energy and total kinetic energy?

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    Replies
    1. Fariza S2T1
      Average kinetic energy is the sum up of the total kinetic energy of molecules and divide by the number of molecules and we get the kinetic energy for one molecule but the total kinetic energy is the sum up of kinetic energy for all molecules... is it correct,madam?😅

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    2. Ainaa S2T1

      Total kinetic energy is the sum of kinetic energies of all the molecules in substance whereas average kinetic energy is the average of kinetic energies of all the molecules.

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  26. good try aina..refer to fariza's answer..exactly, fariza..very good..means that calculation for total kinetic energy:
    total K.E=N(average K.E)

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  27. state example(degree of feedom) of :
    1) monoatomic gas
    2)diatomic gas
    3)polyatomic gas

    very importance to know the type of gas because it is related to degree of freedom.if you master about this you will able to use the correct equation to find average kinetic energy, total kinetic energy and internal energy.

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    Replies
    1. nabilah s3t5
      ex monoatomic gas - He , Ne &Ar
      diatomic gas - H2,O2&N2
      polyatomic- H20,CO2 & NH3

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  28. 1)what means by equipartition of energy?

    2)what means by internal energy?

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    1. athirah S3T5

      1) Equipartition of energy is the average kinetic energy of every degree of freedom of a molecule which is 1/2kT.

      2) Internal energy is the sum of total kinetic energy and total potential energy of the gas molecule.

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  29. Syam S3T5

    equipartition of energy is the total energy of a gas molecule is equally distributed among all the degrees of freedom.While,the internal energy is the energy contained within the system, excluding the kinetic energy of motion of the system as a whole and the potential energy of the system as a whole due to external force fields..

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    Replies
    1. Correct..but i was detect a mistake about last sentence..not excluding but including..U
      CONCLUSION:
      U=K+P.E

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  30. How is about potential energy?i it we consider as energy of the gas for ideal gas?

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  31. Replies
    1. Aiman f3t3

      The intermolecular forces are assumed to be negligible thus the potential energy of the molecules can be neglected

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    2. 👍💯🤩very good aiman..means that internal energy =total K.E

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  32. CONCLUSION:
    1) internal energy=total K.E+total P.E(negligible)
    internal energy=total K.E=(no.of molecules)(average K.E/K.E per molecule)
    why P.E is negligible in IDEAL GAS?

    -vibration of molecules occurs for heavy molecules and at high temperature only
    -vibration energy -too small values of energy-approaching to zero
    -weak attractive force-becomes significant only when molecules close each other.
    at high temperature, kinetic energy of molecules is greater enough to overcome intermolecular attractive force.-weak attractive force(intermolecular force)
    that is why intermolecular forces between molecules - potential energy are negligible in IDEAL gas..
    real gas approching to ideal gas behavior at higher temperature.they are slightly different at high pressure and low temperature.

    there are difference between INTERMOLECULAR FORCES & INTRAMOLECULAR FORCES.

    AVOID YOUR MISCONCEPTION:refer the concept below (EXTRA KNOWLEDGE)
    INTERMOLECULAR FORCES : attractive force between molecules-hold multiple molecules together.e.g: HCl-HCl
    INTRAMOLECULAR FORCES : force that keep the molecule together-keep a molecule intact.e.g H-Cl
    intermolecular force weak compared to the intramolecular force

    2)K.E=translational K.E+Rotational K.E: depends on type of gases(degree of freedom)

    3)translational kinetic energy: in straight line only..same for all type of gases=(degree of freedom=3)


    tricky question:
    1)total translational kinetic energy=total average K.E=N(average K.E)=N(K.E/molecule)
    2)average K.E=K.E for a molecule=K.E/molecule

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