Can somebody explain parts b and e?
The Effectiveness of an Antacid In this activity, you will use a technique known as "back titration" to measure the quantity of hydrochloric acid, 14()( aq) , neutralized by an antacid. This simulates the 6. Dislodge any bubbles that might be stuck in the tips neutralization of stomach acid. of the burettes by letting a few drops of the solutions Equipment and Materials run through. Record the burette readings to 0.01mL. - lab apron 7. Add about 10.0mL of hydrochloric acid to the - chemical safety goggles crushed antacid sample and record the final volume - mortar and pestle of acid in the burette to 0.01mL. - weighing paper 8. Gently swirl the flask with the antacid tablet to dissolve - electronic balance it as much as possible. Add 2-5 drops of bromophenol - graduated cylinders blue indicator. The solution should be ycllow. If it is - two 125mL Erlenmeyer flasks blue, continue to add acid slowly until the solution - 2 burettes, 25mL or 50mL turns yellow and remains yellow after swirling. Again, - 2 utility stands with clamps record the volume of acid remaining in the burette. - stirring rod 9. Titrate the solution with sodium hydroxide solution - 2 small funnels until the solution in the flask turns blue. Watch - pH paper (low range) carefully because the change may not be obvious. - stoppered bottles containing Record the volume of sodium hydroxide solution remaining in the burette. - standardized hydrochloric acid, HCl(aq) 10. Refill the burettes if needed and repeat \$teps 23 and (0.1mol/L)( 6-9 two more times with other samples of the same - standardized sodium hydroxide solution, type of antacid tablet. Record your results carefully. NaOH(aq)(0.1mol/L)$ 11. Repeat the procedure three times using a different - dropper bottle of bromophenol blue indicator brand of tablet. - various antacid tablets (white, unflayoured) 12. Dispose of waste properly. Clean and rinse all 9. Hydrochloric acid is corrosive. Sodium hydroxide is corrosive, equipment as directed. Wash your hands with soap loxic, and an iritant. Awoid spiasting solutions on your skin, and water. (1) in your eyes, or on dotthing immediately rinse any spills with plenty of cool water and inform your teacher. Analyze and Evaluate Never consume anything in the laboratory or remove it for (a) What was measured in this investigation? - consuming outside of the laboratory. (b) Calculate the amount of hydrochloric acid neutralized To unplug the balance, pull directly on the plug rather than by each 1.00g of antacid tablet. Ihe cord. (c) Why must burettes and flasks be clean and dry? min docedure (d) In Step 8, why is it necessary to make sure the indicator stays yellow before titrating with the base? Im 1. Put on your lab apron and safety goggles. (e) Why did the procedure instruct you to first react the 2. Crush an antacid tablet using a mortar and pestle. tablet with acid, and then back-titrate with the base, Tare the balance with the weighing paper. Add about and not just titrate with the acid? What possible 0.4g of the crushed tablet and measure its mass to errors does this additional step introduce? Do you 2 decimal places. Transfer the crushed tablet into an think it was a good idea? Why or why not? Em lirlenmeyer flask. Record the brand of tablet and the mass of your sample. Apply and Extend 1.abel one burette " HCl(aq) ). Rinse the burette with (f) Compare the effectiveness of different antacids. hydrochloric acid, clamp it to a utility stand, and (g) Were you surprised by any of the results? Explain. lhen, using the funnel, fill it with the acid. (h) Research the cost per tablet of each type of antacid label the other burette " NaOH(aq)).Rinsethis that you investigated. Compare the cost effectiveness burette with sodium lydroxide solution, clamp it to a utility stand, and then fill it with the base
