## ICE Table Variables

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Mitchell Koss 4G
Posts: 128
Joined: Sat Jul 20, 2019 12:17 am

### ICE Table Variables

In online module #2, Dr. Lavelle represents the ICE box change without x terms but just by the concentration. In module 3, he uses x as a variable for the change amount. Should we always use variables from this point on? Are there times we would not be able to use variables?

Amy Pham 1D
Posts: 103
Joined: Fri Aug 09, 2019 12:15 am

### Re: ICE Table Variables

Any time when you are given an equilibrium concentration (as opposed to just initial concentrations), you can use that value to determine the changes in concentration for each of the reactants and products. It is only when you don't know the equilibrium concentrations and aren't able to deduce the changes that you would use a variable in place of the concentration changes.

Kishan Shah 2G
Posts: 132
Joined: Thu Jul 11, 2019 12:15 am

### Re: ICE Table Variables

Always use variables in your change row. the coefficient for your change variable corresponds to the coefficient in the chemical equation. Use a negative sign to indicate using up of reactants and a positive sign to indicate production of products.

christabellej 1F
Posts: 109
Joined: Sat Aug 17, 2019 12:17 am

### Re: ICE Table Variables

You also would not have to use variables if any part of your equation includes species that are not in aqueous or gas states. Since a pure solid or liquid would be the same, you would only use variables when determining changes in aqueous/gas reactants and products.

Megan Vu 1J
Posts: 101
Joined: Thu Jul 25, 2019 12:15 am

### Re: ICE Table Variables

Using variables should be essential in establishing the change in molar concentration. However, you should only not use when there is a solid involved or water leftover as a liquid. When you are given equilibrium molar concentrations, you can use that number in order to sometimes determine the change in molar concentration depending on the question.

Also, with variables, you should look at the molar ratio to see if it'd be either 1x or 2x. 2 and other numbers so forth would only be used if the molar ratio had a 2:1 ratio, etc. These can help determine the ice box in order to set up the composition of the equilibrium mixture.

Tiffany_Chen 2K
Posts: 106
Joined: Fri Aug 30, 2019 12:15 am

### Re: ICE Table Variables

Yes, using variables will aid you in calculating different parts of the Kc equilibrium. You will use the quadratic equation to solve for the 'x', then apply to the reactant or product.

Nick Fiorentino 1E
Posts: 102
Joined: Wed Sep 18, 2019 12:16 am

### Re: ICE Table Variables

Using "x" in the ICE tables would definitely be helpful if the problem is complicated enough, but if it's simple and you can figure out the change without variables, that might be easier