Difference between revisions of "Freezing Point Depression"

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(Custom Calculation)
(Custom Calculation)
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Then locate Temperature in the bottom box and select it as well:
 
Then locate Temperature in the bottom box and select it as well:
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 +
[[File:7.png]]
 +
 +
When done the screen should look like this:
 +
 +
[[File:8.png]]
 +
 +
Click OK:
 +
 +
We will need to “Fix” variable to target. In this case it is H2O-Sol (a/k/a Ice) and we want a small value.
 +
 +
[[File:9.png]]
 +
 +
You can enter a small value 1E-06 moles.
 +
 +
[[File:10.png]]
 +
 +
The temperature value can be a "guess" value.
 +
 +
Click on the calculate button.
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 +
In the summary box you will see the calculated temperature:
 +
 +
[[File:11.png]]
 +
 +
This value is similar to the plot value we observed earlier.

Revision as of 14:14, 4 August 2017

Overview

The freezing point depression calculation can be performed in OLI to study the effect of salts on the freezing point of water.

Composition and Performance Survey

One way to identify the freezing point is to perform a composition survey:

Select add a survey from Add a Calculation:

12.jpg

Select a range from specs for Temperature to go from -10 to 10 deg C:

13.jpg

14.jpg

You will see the following plot:

1.png

Custom Calculation

Choose the single point calculation:


2.png

From the Type of Calculation, choose a Custom Calculation:

3.png

This requires some custom specifications:

4.png

Click the Specs button.

5 1.png

This can be a complicated screen. There is an absolute rule for this screen, the number of fixed variables (top box) must equal the number of free variables (bottom box).

Now scroll down in the top box to find H2O-sol and then select it.

6.png

Then locate Temperature in the bottom box and select it as well:

7.png

When done the screen should look like this:

8.png

Click OK:

We will need to “Fix” variable to target. In this case it is H2O-Sol (a/k/a Ice) and we want a small value.

9.png

You can enter a small value 1E-06 moles.

10.png

The temperature value can be a "guess" value.

Click on the calculate button.

In the summary box you will see the calculated temperature:

11.png

This value is similar to the plot value we observed earlier.