# Ph Calculations Pdf

## Calculating pHandpOH Calculate the pH by including the autoionization of water. You will most likely use a simple p H meter in the laboratory. Thus, a strategy is given here to deal with these systems. Skills to Develop Calculate the pH when two weak acids are present in a solution. Recall that a logarithm is simply the exponent that some base number needs to be raised to in order to generate a given number. The voltage that develops is a direct function of the p H of the solution and the circuitry is calibrated so that the voltage is directly converted into the equivalent of a p H value. Other p H papers are more exotic. Use your calculator to obtain these values. When the phenolphthalein changes from colorless to pink, you know that enough base has been added to neutralize all of the acid that is present. When autoionization of water is considered, the method is called the exact pH calculation or the exact treatment. The simplest p H paper is litmus paper that changes from pink to blue as a solution goes from acid to base. If you like the x and y representation, you may use method a. This method is illustrated below.

The indicators are chosen so that the paper takes on a slightly different color over a range of p H values. There is another useful calculation that we can do by combining what we know about p H and expression.

One thing that you should notice about the numbers in the previous examples is that they are very small. For simplicity, we consider two acids in this module, but the strategies used to discuss equilibria of two acids apply equally well to that of two bases. 