Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Integrating a concentration profile

  1. Jan 8, 2013 #1
    Hello-

    I have a diffusion profile, in which I plot the decrease in concentration versus distance of my sample. I am trying to find the increase in mass of the overall sample. How would I do this?

    I have integrated the function and am wondering what type of information that would supply my. Units would be concentration*distance. moles*m
     
  2. jcsd
  3. Jan 8, 2013 #2

    mfb

    User Avatar
    2016 Award

    Staff: Mentor

    How are concentration of something and "mass of the overall sample" related?
    If your diffusion (and concentration) is not one-dimensional, you should consider this in the integral.
    "Moles" is not a concentration.
     
  4. Jan 9, 2013 #3
    I did not actually plot the concentration. My diffusion profile consists of an initial amount of substance a in moles n(a) and plots it as a function of distance in the sample. so I am trying to figure out what information I get when I integrate this profile. moles*meters would be the units
     
  5. Jan 9, 2013 #4

    mfb

    User Avatar
    2016 Award

    Staff: Mentor

    Again, "moles" is not a concentration. Moles as a function of distance are meaningless, unless it means the total amount of substance between that point and some other point. In that case, I don't see any application of the integral.
     
  6. Jan 9, 2013 #5
    Concentration is usually expressed as moles per unit volume (e.g., moles/cc). The integral of this is moles/cm2. To get the total number of moles in the sample, you then need to multiply by the cross sectional area of the sample.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Integrating a concentration profile
  1. Gas Concentration (Replies: 2)

Loading...