Integrating a concentration profile

In summary, the conversation discusses a diffusion profile and how to find the increase in mass of the overall sample. They mention integrating the function and considering the dimensions of the sample. It is noted that "moles" is not a concentration and that concentration is usually expressed as moles per unit volume. The units for the integral of concentration are also mentioned.
  • #1
DiffusConfuse
22
0
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
 
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  • #2
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.
 
  • #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
 
  • #4
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.
 
  • #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.
 

What is a concentration profile?

A concentration profile is a graphical representation of the distribution of a substance within a given system, typically in terms of concentration as a function of distance or time.

Why is integrating a concentration profile important?

Integrating a concentration profile is important because it allows us to calculate the total amount of a substance present in a system, which is necessary for many scientific applications such as determining reaction rates or understanding diffusion processes.

How do you integrate a concentration profile?

To integrate a concentration profile, you first need to determine the mathematical function that describes the profile. Then, you can use techniques such as the trapezoidal rule or Simpson's rule to numerically integrate the function and calculate the total concentration.

What are some common methods for creating a concentration profile?

There are several methods for creating a concentration profile, including experimental techniques such as chromatography or spectroscopy, as well as theoretical models based on diffusion equations or reaction kinetics.

What factors can affect the shape of a concentration profile?

The shape of a concentration profile can be affected by a variety of factors, including the initial concentration of the substance, the properties of the system (such as its size or shape), and any external forces or gradients (such as temperature or pressure) that may be present.

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