pH Study General Chemistry 101/102 Laboratory Manual University of North Carolina Wilmington

pH Study Purpose Safety Considerations To study the differences between strong and weak acids and bases To study reactions of water with various salt compounds To learn the concept of buffering capacity Safety Considerations Safety glasses must be worn throughout the entire experiment, even when cleaning glassware to prevent damage due to strong acids and bases. Be cautious when using unknown solutions and clean up any spills immediately. Contact with strong acids or bases will affect skin and create holes in clothing. Wash the affected area thoroughly if you suspect any skin contact any of unknown solutions. Flush all wastes down the drain with plenty of water.

pH Study Procedure Connect the Tablet computer, Microlab unit, and the pH electrode as shown in the illustration below.

pH Study Procedure To begin determining pH measurements on the computer, click on the Applications folder, and select the Microlab prompt. Then double click on the “pH Titrations” prompt as shown below.

pH Study Procedure Click on the experiment entitled “pH Acid-Base – Temperature Manual Titration”, as shown below.

pH Study Remove the pH electrode from the pH =7 buffer and place in a beaker of DI water. Use this beaker to store the pH electrode between sample measurements. Rinse the pH electrode with DI water from a squeeze bottle, letting the water run into a smaller beaker designated for waste. Dab the end of the electrode with a Kimwipe and place the electrode into your sample solution. pH values will be displayed in the lower right hand corner of the screen. Record these values on your data sheet upon each pH determination. When experiment is complete, place the pH electrode back into the pH=7 buffer solution. Procedure