Question

If you are not given the initial concentration of a particular reactant or product in an ICE table question, what should you do?

Answer 1

When not given the initial concentration of a reactant or product in an ICE table, assume it's zero if it's a product, or seek to calculate the reactants' initial concentration using other provided data such as equilibrium concentrations and the equilibrium constant, Kc.

Step-by-step explanation:

If you are not given the initial concentration of a particular reactant or product in an ICE table question, you can usually assume that the initial concentration is zero, particularly if the substance is a product of the reaction. This is because products are typically not present before the reaction begins. However, if the substance is a reactant and you're not given its initial concentration, it would be an unusual scenario since reactants must be present for the reaction to occur. If this happens, you may need to look for additional information that can help you indirectly calculate the initial concentration, such as given equilibrium concentrations and the equilibrium constant (Kc).

To develop an ICE table, you:

1. Identify the direction in which the reaction will proceed to reach equilibrium.
2. Develop an ICE table by listing Initial concentrations, Change that occurs as the reaction proceeds, and Equilibrium concentrations.
3. Calculate the concentration changes and, subsequently, the equilibrium concentrations.
4. Confirm the calculated equilibrium concentrations by substituting these values into the equilibrium constant expression to ensure it equals the provided Kc.

By presenting all this information in an ICE table format, you can methodically approach the problem and solve for unknown concentrations. If you're provided with the initial concentrations of the reactants and the equilibrium concentration of a product, you can derive terms for the equilibrium concentrations of the reactants using the ICE table. For example, if you know that product concentration at equilibrium by x, and the stoichiometry of the reaction, you can determine the changes in reactant concentrations and hence find their equilibrium concentrations.