What is the de Broglie wavelength of an oxygen molecule, O2 traveling at 521 m/s? Is the wavelength much smaller or much larger than the diameter of an atom. (on the order of 100 pm)
De Broglie wavelength = h/mv
h = Planck's constant in J*s.
m is mass in kg.
v is velocity in m/s
Okay for this one I did
6.63 X 10^-34 J*s/ (?kg) (6210 m/s)
I don't understand how I get the kg for the problem
Let's see now. Do you have any idea how large a number 3.01 x 10^23 grams is? Do you think 1 single atom of oxygen can weigh
600,000,000,000,000,000,000,000 grams. That's one heavy atom.
sorry I copied the wrong problem it is supposed to be: 521 m/s not 6210 m/s
6.63 X 10^-34/ (? kg)(521 m/s)
How do I get the kg for this problem
1 mol O2 has a mass of 32 g and contains 6.02 x 10^23 molecules OR 2 x 6.02 x 10^23 atoms. Therefore, 1 atom of oxygen has a mass of ???
3.01 x 10^23 ???
yes I know how big that is but I figured that you had 2 atoms of 6.02 x 10^23 so I divided by 2 to get the mass of 1 mol which is 3.01 X 10^23...
why wouldnt you just take the 100 pm and make it into kg.
Aha!. I wondered how you did it. But you KNOW 1 atom of oxygen can't possibly weigh that much. You can't even see 1 atom of oxygen so you know the mass of 1 atom must be very small. And your number isn't very small; it is very large. The mass of 1 mol is 32 grams. I told you that in my first response.
1 mol (not 1 molecule) has a mass of 32 grams and contains 12.04 x 10^23 atoms of oxygen. So 1 atom must have a mass of
(32 g/mol) x (1 mol/12.04 x 10^23 atoms) = ?? grams/1 atom.
so that equals 2.66 grams/ 1 atom
now where do I go from there
Absolutely not!
32/12.04 x 10^23 = WHAT. You dropped the exponent again.
My calculator gives me 2.66 x 10^-23 grams.
What next? Change this to kg, you have the other numbers, calculate lambda. That will come out in meters.
2.66 X 10 ^-23 (0.001 kg/1 g) = 2.66X 10^-26
that is what I want is kg