HW - #17

[Alexa Marinelli-1B]

The average speed of a diatomic fluorine molecule at 25 ∘C is 442.4 m⋅s−1 . What is the average wavelength of a fluorine molecule at this temperature? Assume that the molecule acts as a single particle. For this question I used the equation lambda = h / mv. When converting diatomic fluorine, I multiplied the mass by 2 and divided by avogadro's constant, and converted to kg, which gave me 6.3x10^-26. I plugged in the numbers into the equation: planck's constant /(6.3x10^-26)(442.4) which gave me 2.37 x 10^-11. The feedback that was given was that "You may have used the mass of a single fluorine atom to calculate the wavelength. Recall that fluorine is a diatomic molecule, therefore it contains two fluorine atoms." If someone can explain my error or let me know how to change it, it would be a huge help.

[Shria G 2D]

Hi,
I used the same equation, lambda = h/mv but I had a different value for mass of the nitrogen molecule.
14.0067 is the molar mass of nitrogen so I did (14.0067 g/mol)(1 mol/6.02x10^23 atoms)(2 atoms N/1 molecule N2)(1 kg/1000g) which is 4.65 x 10^-26 kg. I plugged this into the equation and I got 3.22 x 10^-11 m for the final answer.