Help with thermodynamics question please

[pureouchies4717]

this is the question:

From what height must an oxygen molecule fall in a vacuum so that its kinetic energy at the bottom equals the average energy of an oxygen molecule at 300 K?

i know how to find the average energy:

average energy= (3/2)K(b)T
= 6.21 x 10^-21

i also know how to find the kinetic energy of an oxygen molecule:

K= 1/2 m v(rms)^2

the only problem is that i don't know how to get the distance. can someone please help

 

[marlon]

Use conservation of total energy and keep in mind that gravity is the force that is responsible for making the molecule fall down.

regards
marlon

 

[pureouchies4717]

thanks!

so then:

6.21 x 10^-21 = mgh

is that the right setup?

 

[marlon]

thanks!

so then:

6.21 x 10^-21 = mgh

is that the right setup?

yes

marlon