MATERIALS computer 0.050 M NaOH Vernier computer interface various cola soft drinks, decarbonated Logger Pro distilled water Vernier pH Sensor ring stand 50 mL buret utility clamp 100 mL graduated cylinder magnetic stirrer (if available) 250 mL beaker stirring bar PROCEDURE 1. Obtain and wear goggles. 2. Use a graduated cylinder to measure out 40 mL of a decarbonated cola beverage and 60 mL of distilled water into a 250 mL beaker. CAUTION: Do not eat or drink in the laboratory. 3. Place the beaker on a magnetic stirrer and add a stirring bar. If no magnetic stirrer is available, you need to stir with a stirring rod during the titration.
35 - 2 Chemistry with Vernier Computer 35 4. Connect the pH Sensor to the computer interface. Prepare the computer for data collection by opening the file “35 Phosphoric Acid” from the Chemistry with Vernier folder of Logger Pro . 5. Use a utility clamp to suspend a pH Sensor on a ring stand as shown in Figure 1. Position the pH Sensor in the HCl solution and adjust its position so that it is not struck by the stirring bar. 6. Obtain a 50 mL buret and rinse the buret with a few mL of the 0.050 M NaOH solution. CAUTION: Sodium hydroxide solution is caustic. Avoid spilling it on your skin or clothing. Dispose of the rinse solution as directed by your teacher. Use a utility clamp to attach the buret to the ring stand as shown in Figure 1. Fill the buret a little above the 0.00 mL level of