January 11, 2025, 08:06:41 AM
Forum Rules: Read This Before Posting


Topic: Determining the rms molecular speed  (Read 8857 times)

0 Members and 1 Guest are viewing this topic.

Offline Lindsay

  • Regular Member
  • ***
  • Posts: 24
  • Mole Snacks: +2/-0
Determining the rms molecular speed
« on: October 19, 2008, 12:08:54 AM »
Hello,

I am trying to calculate the rms speed using my TI-83 Calculator and it is just not working for me. Can someone walk me through on how to enter it into the calculator?

Calculate the rms speed of O2 molecules in a cylinder at 21 C and 15.7 atm.
u= (3 * 8.31 kg * m2/(s2*K*)* 294 K/
           32.0 * 10(-3) kg/mol              )  1/2   = 479 m/s

The result is 479 m/s
How do you enter that whole equation in a TI-83 Calculator?
I can not get it to work.. It is not giving me that answer.
Please help.
Thanks,
Lindsay

Offline Astrokel

  • Full Member
  • ****
  • Posts: 989
  • Mole Snacks: +65/-10
  • Gender: Male
Re: Determining the rms molecular speed
« Reply #1 on: October 19, 2008, 04:41:25 AM »
hi lindsay, sorry but i dont quite understand your working?

Are you using PV=nRT and 1/2 m <c2> = 3/2kT or PV= 1/3 Nm <c2> ?

im using TI-84 and its quite user friendly, do you know how to store values? And when using exponential, use the E-3 instead of 10^(-3)
No matters what results are waiting for us, it's nothing but the DESTINY!!!!!!!!!!!!

Offline Lindsay

  • Regular Member
  • ***
  • Posts: 24
  • Mole Snacks: +2/-0
Re: Determining the rms molecular speed
« Reply #2 on: October 19, 2008, 12:08:48 PM »
I using this formula "The root-mean-square (rms) molecular speed
u=root(I meant the root sign followed by) 3 RT/Mm

where R is the Molar gas constant, T is the absolute temperature, and Mm is the molar mass for the gas

I don't know how to plug all that into my TI-83 calculator
Can someone help

Lindsay

Offline Astrokel

  • Full Member
  • ****
  • Posts: 989
  • Mole Snacks: +65/-10
  • Gender: Male
Re: Determining the rms molecular speed
« Reply #3 on: October 19, 2008, 12:34:07 PM »
I'm not sure if there is any different with my TI-84 plus, anyway,

(3x8.31x294)/(32E-3))^0.5

find EE for exponetial power and you can find ^ on your calculator as well.
No matters what results are waiting for us, it's nothing but the DESTINY!!!!!!!!!!!!

Offline nj_bartel

  • Sr. Member
  • *****
  • Posts: 1487
  • Mole Snacks: +76/-42
Re: Determining the rms molecular speed
« Reply #4 on: October 19, 2008, 12:37:06 PM »
I'm not sure if there is any different with my TI-84 plus, anyway,

(3x8.31x294)/(32E-3))^0.5

find EE for exponetial power and you can find ^ on your calculator as well.

I'm not sure what the formula is, so I'm not sure how to correct you, but you do have too many closing  parentheses and would get an error in your calc for it

Sponsored Links