Buffers maintain pH through small additions of acid or base and are composed of an acid and its conjugate base, with the pKa slightly above the desired pH. Dilutions can be calculated using the dilution formula of M1V1 = M2V2. The pH of solutions can be determined through litmus paper, pH paper, indicators, or a pH meter. Calculations must be completed and checked by the TA in advance of the experiment.

1. Chemistry is pHun

2. Buffers Maintains pH with small additions of acid or base Composed of an acid and its conjugate base pKa should be + of desired pH Conjugate base from acid differs by only one H+

3. Dilution Calculations Dilution formula Use only for dilutions and not for titrations M1V1 = M2V2

4. Using a Volumetric Flask

5. Ways to determine the pH Litmus Paper: indicates if acidic, basic, or neutral by color. pH paper: Gives an approximate pH of solution by color of the paper. Indicators: a chemical added to the solution which tells pH by color change. pH Meter: monitors pH using the Labpro and gives a readout of the measured pH

6. Calculations See the PowerPoint posted on Blackboard under “Experiments” to get help with the calculations You MUST have questions 1 and 3 completed and checked by the TA before you start the experiment

7. Experiment Tips Come to lab prepared Complete the necessary calculations and get help IN ADVANCE Review information on buffers in Chang