How to Calculate the Mass of a ^{14}N Atom?

  • Thread starter Thread starter WolfOfTheSteps
  • Start date Start date
  • Tags Tags
    Atomic Weight
Click For Summary

Discussion Overview

The discussion revolves around calculating the mass of a ^{14}N atom, particularly in the context of determining the de Broglie wavelength of the atom when laser cooled to a specific temperature. The scope includes aspects of chemistry and physics relevant to atomic mass and its implications in calculations.

Discussion Character

  • Homework-related
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant seeks clarification on how to calculate the mass of ^{14}N, expressing uncertainty about their chemistry knowledge.
  • Another participant suggests looking up the mass on a periodic table, noting that it is given in g/mol and relates to Avogadro's number.
  • A participant acknowledges the mass number (14) and raises the point that different isotopes (^15N, ^16N, etc.) have different masses, questioning how to account for this in calculations.
  • One response indicates that while the mass number is technically relevant, it may not significantly impact the calculation at hand.
  • Another participant proposes using a specific value of 14.000000000000000000000000 g/mol for the mass of ^{14}N, suggesting it is straightforward.
  • A later reply challenges the simplicity of using 14.0000 g/mol, stating that the actual mass of ^{14}N is not exactly 14.0000 due to mass deficits, particularly in comparison to ^{12}C.

Areas of Agreement / Disagreement

Participants express differing views on the significance of the mass number in calculations, with some asserting it may not matter much while others emphasize the importance of considering isotopic differences. The discussion remains unresolved regarding the exact mass to use for ^{14}N.

Contextual Notes

There are limitations in the discussion regarding the assumptions made about the mass of isotopes and the implications of using rounded values in calculations. The relevance of mass deficits is also noted but not fully explored.

WolfOfTheSteps
Messages
134
Reaction score
0

Homework Statement


What is the de Broglie wavelength of an [itex]^{14}\mbox{N}[/itex] atom that has been laser cooled to a temperature of T=77K.

The Attempt at a Solution



This is a trivial problem, and I can do the physics... But how do I calculate the mass of [itex]^{14}\mbox{N}[/itex]? My chemistry is obviously less than crappy.

Thanks.
 
Physics news on Phys.org
You can look up the mass on a periodic table, it gives the mass in g/mol, where one mol contains 6.02x10^23 atoms (Avogadro's number).
 
I know that much, but what does the 14 do in [itex]^{14}\mbox{N}[/itex]. I know that the 14 is the "mass number." So, surely [itex]^{14}\mbox{N}, ^{15}\mbox{N}, ^{16}\mbox{N},[/itex] etc have different masses, and you can't just use the mass that's on the periodic table.

Isn't this true? In that case, how do I take the 14 into account?
 
Use 14.000000000000000000000000 g/mol.

Pretty easy, huh?
 
chemisttree said:
Use 14.000000000000000000000000 g/mol.

Pretty easy, huh?

Probably as wrong as easy... Not that it matters much, but 14N mass is not 14.0000. 12C is 12.0000, mass deficit per nucleon for nitrogen is slightly different.



 

Similar threads

Chemistry How to get the atomic weight of O 16g/mole to amu?
  • · Replies 10 ·
Replies
10
Views
3K
How to get atoms of something having % of mass?
  • · Replies 14 ·
Replies
14
Views
2K
Chemistry How to calculate the maximum charge of an atom or a molecule
  • · Replies 6 ·
Replies
6
Views
2K
12 amu and 1.9924 X 10^-23g express the mass of a atom of C?
  • · Replies 1 ·
Replies
1
Views
2K
Atomic Mass: Helium-4 Nucleus Contribution
  • · Replies 7 ·
Replies
7
Views
4K
What is the difference between amu and u in atomic mass units?
  • · Replies 1 ·
Replies
1
Views
7K
Chemistry Finding the Chemical Formula and Relative Molecular Mass
  • · Replies 13 ·
Replies
13
Views
4K
If atoms are neutral, how do they share electrons
  • · Replies 6 ·
Replies
6
Views
2K
Calculating Charge on 1 g N3- Ions: Where Did I Go Wrong?"
  • · Replies 6 ·
Replies
6
Views
11K
Why Are Multiple Quantum Numbers Allowed in a Hydrogen Atom?
  • · Replies 2 ·
Replies
2
Views
4K