Record all your experimental data in the table. DATA TABLE MEASUREMENTS #1 #2 #3 Concentration of NaOH _______mol/L ________mol/L _______mol/L Initial reading of base buret ________ mL ________ mL ________ mL Final reading of base buret ________ mL ________ mL ________ mL Volume of NaOH used ________ mL ________ mL ________ mL Initial reading of acid buret ________ mL ________ mL ________ mL Final reading of acid buret ________ mL ________ mL ________ mL Volume of HCl used ________ mL ________ mL ________ mL B. Obtain about 120 mL of HCl solution in a 150 mL beaker. Label the beaker. C. Rinse one buret with approximately 10 mL of the HCl solution, and let the liquid drain through the buret tip into an empty 250 mL "waste" beaker. Repeat this procedure twice more, using new 10 mL samples of HCl solution each time. D. Refill the buret so that the meniscus of the solution is above the 0 mL mark. Position the buret in a double buret clamp on a ring stand. Let some of the solution run rapidly from the buret to expel all air bubbles from the tip and to bring the level of the solution down to the calibrated region of the buret. If there is a drop of solution hanging on the tip of the buret, remove it by touching the drop to the inside wall of the 250 mL beaker. E. Hold a piece of white paper behind the meniscus, and read the initial volume of the solution at the bottom of the meniscus. Your eye must be at the same level as the meniscus. F. Obtain approximately 120 mL of NaOH in a second labeled 150 mL beaker. Obtain a second buret and repeat Parts C to E, using the HCl. G. Let approximately 20 mL of HCl to flow from the acid buret into a clean 250 mL Erlenmeyer flask. Add two drops of phenolphthalein. H. Place the Erlenmeyer flask under the tip of the base buret. A piece of white paper placed under the flask will make it easier to see the color changes. While - 4 -
GHS Honors Chemistry Acid-Base Titration Lab Name: ____________________________________ Date: _______ Block: _______ continuously swirling the flask to ensure thorough mixing, run in the NaOH solution from the buret. Initially, a pink color will appear at the point where the NaOH comes in contact with the solution in the flask; however, this color disappears quickly. As the endpoint nears, the color will disappear more slowly.
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- Spring '16
- Chemistry, ml, Erlenmeyer flask