Finding the gas based off of mass

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SUMMARY

The discussion focuses on determining the identity of a gas based on its average kinetic energy and impulse squared values. The average kinetic energy is given as = 6.5 x 10-21 J and 2> = 1.8 x 10-45 kg2m2s-2. Through calculations, participants deduce the mass of the molecule to be approximately 1.38 x 10-25 kg, leading to the conclusion that the gas is likely Krypton (atomic weight 83.8) or Hydrogen Bromide (HBr, molecular weight 81). The discussion emphasizes the importance of understanding molecular weight and the relationship between mass and the number of protons and neutrons in identifying gases.

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  • Understanding of kinetic energy equations in physics
  • Familiarity with molecular weight and atomic mass concepts
  • Basic knowledge of the periodic table and gas properties
  • Proficiency in algebraic manipulation of equations
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  • Research the molecular weights of common gases, focusing on Krypton and HBr
  • Study the relationship between molecular weight and the number of protons/neutrons
  • Learn about kinetic theory and its applications in gas behavior
  • Explore experimental methods for determining molecular weight in gases
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Chemistry students, educators, and professionals in the field of physical sciences, particularly those interested in gas properties and molecular identification.

  • #31
mk9898 said:
Thanks for your expertise. Just to remove any doubt I have two questions: 1) how is the division from the mass/proton mass = atomic weight? That would just be a scalar. 2) How does one find the total amount of the protons of an element?
The only information we had was the molecular weight. You asked a good question, but other than by looking at the periodic table, I don't know of a simple experiment that will tell you what the atomic number (number of protons) is given the atomic weight.
 
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  • #32
Yea apologies I meant molecular weight. But molecular weight/proton weight = atomic weight? How can that be?
 
  • #33
mk9898 said:
Yea apologies I meant molecular weight. But molecular weight/proton weight = atomic weight? How can that be?
We computed the number of neutrons plus protons. (molecular weight). Since they both have very nearly the same mass, the only thing we knew is that the sum of the neutrons and protons was 83(1.67 E-27) kg. There was no info as to whether we had 40 protons or 41 or 42, etc. Usually the number of protons and neutrons in an atom are about equal, plus or minus one or two or so. ## \\ ## The quickest way to determine the number of protons is to identify the chemical properties of the material, so that you know what the molecule or atom is, and then simply look it up in the periodic table. Experiments with molecular dynamics determine the mass (molecular weight), but these experiments do not give any info on the number of protons.
 
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  • #34
Ok I understand now thank you. I just watched a video that gave some more background on the subject. Thank you a lot for your effort!
 
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