Use Coupon: CART20 and get 20% off on all online Study Material

Total Price: R

There are no items in this cart.
Continue Shopping
Get instant 20% OFF on Online Material.
coupon code: MOB20 | View Course list

Get extra R 650 off

				   What is the de broglie wavelength of He at 25 celcius?

7 years ago


Answers : (1)


We know that the de broglie wavelength is given by

l = h/p = h/mv

We know that the mass of 1 mole of He atoms is 4 g. 

Therefore, mass of one He atom = 4/(6.023 x 1023) = 6.64 x 10-24 g

Using the Kinetic theory of gases, we can relate temperature to velocity of molecules.

The Kinetic theory of gases says that in thermal equilibrium, the Kinetic energy of one mole of atoms in a gas is given by

KE = (3/2)RT

Therefore, KE of one mole of He atoms = (3/2)* 8.314*(25+273) [Convert 25 C to K]

= 3716.358 J

Hence, Kinetic Energy of one He atom = 3716.358/(6.023 x 1023) = 6.17 x 10-21 J

Now, the Kinetic Energy = (1/2)mv2 .

So, 6.17 x 10-21 = (1/2)(6.64 x 10-24)v2

v2 = 1858.433

So, v = sqrt(1858.433) = 43.11 m/s

Hence momentum mv = 6.64 x 10-24 * 43.11 = 2.86 x 10-22 kg.m/s

So, finally, de broglie wavelength l = h/p = 6.626 x 10-34 / 2.86 x 10-22 = 2.31 x 10-12 m

7 years ago

Post Your Answer

Other Related Questions on Physical Chemistry

lithium tetra borate is considered as acidic flux whereas lithium meta berate is considered basic fluxwhat is the criteria for it?
In Lithium metaBorate the no. of hydrogens can be donated is superficcil than in compare to Li tetra Borate. Therfore by definition of acid – base lithium tetra borate is considered as...
2017 years ago
thermodynamics,chemistry question is attached....................................
U=nc(at const. vol.)dt=5000J, but how come the answer is 6000J.........................................................
Naveen Shankar one month ago
The system is working at constant pressure. hence Change in internal energy is given as: U = F/2 nRt + (F/2+1)nRt here t is change in temp from final to initial. F is degree of freedom. n...
Vikas TU one month ago
what is the oxidation state of sulphur in H 2 S 2 O 8, Na 2 S 4 O 8 and Na 2 S 2 O 3.
@ bhavika in H2S2O8, since 2 oxygen is forming the peroxide linkage here , so, the o.n of sulpher will be +6 . and in the 2 nd case NA2S4O8 , in thaat case take sulpher o.n to be x after...
Umakant biswal 3 months ago
You no longer have to wait desperately for someone to help resolve your doubt. You can chat with IITians live, 24/7 (even at 3AM!) and get your doubt resolved instantly. Try the HashLearn...
Ankit 3 months ago
u need to remember that which structure have peroxide linkage and which structure have not , there are only some exception with peroxide linkage , go through the ncert redox reaction...
Umakant biswal 3 months ago
formula to find the number of Total nodal planes####### star star star star star star star star star star start start start start start start
@ RAHUL u can calculate the no of nodal planes by the following formula no of nodal planes in an orbitals = azimuthal quantum number so, that for s orbitals , l=0 , so, nodal planes , l-=0...
Umakant biswal 9 days ago
Write differences between double salt and common salt.
Double salts are formed by mixture of two normal or simple salts obtained through crystallization. for example-dolomite. Common salt is the common name of NaCl and isan example of normal...
Mudit 2 months ago
Why do we prefer Friedel craft acylation to Friedel craft alkylation in preparation of alkylbenzene?
There are many electrophilic substitution reactions associated with benzene and benzene derivatives. However, very few of them involve formation of a carbon-carbon bond, one of the primary...
dolly bhatia 2 months ago
Friedel craft acylation inviles always the double bonded Oxygen with R or other group which leads to decrease in the density of the electrons. .Where as alkyl group -R shows +I effect which ...
Vikas TU 2 months ago
View all Questions »

  • Complete JEE Main/Advanced Course and Test Series
  • OFFERED PRICE: R 15,000
  • View Details
Get extra R 3,750 off

Get extra R 650 off

More Questions On Physical Chemistry

Ask Experts

Have any Question? Ask Experts

Post Question

Answer ‘n’ Earn
Attractive Gift
To Win!!!
Click Here for details