Practice Problem: ICE Box Calculations

Professor Dave explains how to calculate equilibrium concentrations using an ICE box method. The video covers setting up the equilibrium expression, using stoichiometry to determine changes in concentration, and solving a quadratic equation to find the equilibrium concentrations of PCl5, PCl3, and Cl2. The tutorial emphasizes understanding the process and provides additional resources for further learning.

What is the initial concentration of PCl5 in the equilibrium system?

• 1.00 molar

• 2.00 molar

• 0.50 molar

• 0.00 molar

What is the equilibrium constant (Kc) for the given reaction?

• 0.0411

• 0.0311

• 0.0211

• 0.0112

In the ICE box setup, what is the change in concentration for PCl5?

• -2x

• -x

• +x

• +2x

What is the equilibrium expression for the reaction?

• [Cl2]/[PCl3]

• [PCl3][Cl2]/[PCl5]

• [PCl5]/([PCl3][Cl2])

• [PCl3]/[Cl2]

Which method is used to solve the quadratic equation in this context?

• Graphical method

• Completing the square

• Factoring

• Quadratic formula

What is the equilibrium concentration of PCl3?

• 0.00 molar

• 0.865 molar

• 0.135 molar

• 1.00 molar

Why is the negative solution for x discarded?

• It is mathematically incorrect.

• It results in a higher concentration for PCl5.

• It is not a real number.

• It results in negative concentrations for products.