This MedLibrary.org supplementary page on ICE table is provided directly from the open source Wikipedia as a service to our readers. Please see the note below on authorship of this content, as well as the Wikipedia usage guidelines. To search for other content from our encyclopedia supplement, please use the form below:
Related Sponsors
An ICE table or ICE chart is a tabular system of keeping track of changing concentrations in an equilibrium reaction. ICE stands for "Initial, Change, Equilibrium". It is used in chemistry to keep track of the changes in amount of substance of the reactants and also organize a set of conditions that one wants to solve with. Occasionally, the chemical reaction is written at the top of the table, resulting in a RICE table.
Example
To illustrate the process, consider the case of dissolving a weak acid, HA, in water. How can the pH be calculated? First write down the equilibrium expression.
- HA
A- + H+
The columns of the table correspond to the three species in equilibrium.
| [HA] | [A- | [H+ | |
| I | c0 | 0 | 0 |
| C | -x | +x | +x |
| E | c0 - x | x | x |
The first row, labelled I, has the initial conditions: the concentration of acid is c0 and it is initially undissociated so the concentrations of A- and H+ are zero.
The second row, labelled C, specifies that when the acid dissociates, its concentration changes by an amount -x and the concentrations of A- and H+ both change by an amount +x. This follows from the equilibrium expression.
The third row, labelled E, is the sum of the first two rows and shows the concentrations at equilibrium.
It can be seen from the table that at equilibrium [H+ = x.
To find x the equilibrium constant must be specified.
![K_a = \frac{[H^+][A^-]}{[HA]}](http://upload.wikimedia.org/math/1/7/9/1797ef4d5bb0d98ca3803b0932e09832.png)
Substitute the concentrations with the values found in the last row of the ICE table.
With specific values for c0 and Ka this equation can be solved for x. Assuming[1] that pH = -log10[H+ the pH can be calculated as pH = -log10x.
References
- ^ Strictly speaking pH is equal to -log10{H+} where {H+} is the activity of the hydrogen ion. In dilute solution concentration is almost equal to activity
Wikipedia content modification information:
- This page was last modified on 31 August 2008, at 05:55.
Wikipedia Authorship and Review
Wikipedia content provided here is not reviewed directly by MedLibrary.org. Wikipedia content is authored by an open community of volunteers and is not produced by or in any way affiliated with MedLibrary.org.
Wikipedia Usage Guidelines
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article on "ICE table".
The URL for this specific entry is:
All Wikipedia text is available under the terms of the GNU Free Documentation License. (See Copyrights for details). Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc.