ICE Box Problems

One type of problem that was more detailed and difficult within the last lesson was problems called ICE box problems. These types of problems are designated solely for when you identify the acid or base is weak, but still want to find the pH of it. You cannot use the same system as you would for the strong acids and bases, but instead use this. To set up the problem you first write the letters ICE vertically along the left hand side. The I stands for initial, the C stands for change and the E stands for equilibrium, and the chemical equation is above the box, horizontally. Next to the I is always the molarity given to you in the problem, and going across will be two dashes, since no data will be shown there. Next, in the C column, you will place a -x. +x, +x, and finally in the E column you will add the two columns up. Then, this information will be put into the equation Ka= [H+][ClO-]/[HClO]. This will further turn into a quadratic equation when numbers are plugged in, and you must solve for x. An easy way to do this is to graph the quadratic and identify the zeros with a function on the calculator. The final step is to convert into pH with the equation pH=-log[H+].
Here is a picture and some links to visually understand and practice this concept:
http://www.chem.purdue.edu/gchelp/howtosolveit/Equilibrium/ICEchart.htm
https://www.youtube.com/watch?v=tT-2xk9ZG_A

capthttp://i.ytimg.com/vi/3HvZxGhuiSE/0.jpg