CHEM 104 Experiment 5: Buffers - Portage Learning

CHEM 104 Experiment 5: Buffers - Portage Learning Purpose: The purpose of this lab is to determine how buffers affect the pH of a solution in order to observe how a buffer is resistant to pH changes. Additionally, we determined how enzymes activity is affected by pH. Procedure: Part 1: Determine pH of sodium acetate in water & buffer 1. 2 pH electrodes are place in 2 separate beakers, one filled with tap water & one is filled with a pH 7 buffer (both have an approximate pH of 7) 2. A scoop of sodium acetate is added to the water & to the buffer 3. The solutions are swirled with a stirring stick to mix 4. We then observed the pH change of each solution Part 2: Determine pH of sodium acetate in water & buffer 1. 2 pH electrodes are place in 2 separate beakers, one filled with tap water & one is filled with a pH 7 buffer 2. 5 drops of HCl added to the water & to the buffer 3. The solutions are swirled with a stirring stick to mix 4. We then observed the pH change of each solution 5. An addition few drops of HCl was added to the water & to the buffer 6. We then observed the pH change of each solution Part 3: Equal concentrations of base & acid 1. A 50 mL solution of sodium lactate & lactic acid were placed in a beaker 2. A pH electrode was place in beaker, which was 3.85 3. Concentrations were 0.5 & 0.5 for both solutions (equal concentrations) Part 4: Higher concentration of lactate base than acid 1. A solution of sodium lactate & lactic acid were placed in a beaker, with more base present 2. We expect a pH of about 4.22 3.