Achieve Question 17 [ENDORSED]

[Angela_Li_1J]

The question asks: "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, can I use the De Broglie equation? If so, do I use the atomic mass of fluorine for the mass?

[joshua_quinn_1C]

Hello! Yes, I think you can use De Broglie's wavelength equation for this. However, since it says "diatomic fluorine molecule" I think you would use the molar mass of the molecule F₂.

[Sevde Coban 2J]

You would use the molar mass of F2 but before you can use this mass in de Broglie’s equation, you need to divide that molar mass of F2 by Avogadro’s constant (6.02214x10^23 mol^-1) to get the molar mass in g/molecule. You also need to divide that by 1000 because you need to get the units to be in kg, not grams.

[Alekhya_Pantula_2E]

Hello! Since they give you the velocity and you are looking at the wavelength of a particle, you can use the DeBroglie wavelength equation. And then you can use the regular molar mass of a Fluorine atom and then just multiply by 2.

[Marleena]

Yes I used the de broglie equation for this question. You would use the atomic mass for this, however it says it is diatomic, so you would multiply the mass by 2.

[Holland Smith 3C]

I followed all the steps recommended above, but still didn't get the right answer. I started by finding the molar mass of fluorine and dividing by Avogadro's number, then multiply by 2 (and converted into kg). after that I simply plugged in my H (with kgm2s-2) the mass I found, and the speed given. I am not really sure what's wrong, so if anyone could explain please lmk!