### Quiz 3 Prep #7, setting up ICE box

Posted:

**Mon Dec 01, 2014 4:07 pm**Problem: For the following reaction, if the initial concentration of PCl3 (g) is 1.0M and x is the equilibrium concentration of P4 (g), what is the expression for the equilibrium constant? PCl3 <--> P4 + Cl2

I balanced the equation... 4PCl3 <--> P4 + 6Cl2

In setting up my ICE box, I realize that the initial for P4 is 0, and that you would add "x" to get your equilibrium value...I still don't understand what to add/subtract for the other components of the reaction? Would I add 6x for Cl2 and subtract 4x from PCl3 because of the stoichiometric coefficients?

Thank you!

I balanced the equation... 4PCl3 <--> P4 + 6Cl2

In setting up my ICE box, I realize that the initial for P4 is 0, and that you would add "x" to get your equilibrium value...I still don't understand what to add/subtract for the other components of the reaction? Would I add 6x for Cl2 and subtract 4x from PCl3 because of the stoichiometric coefficients?

Thank you!