Chem Lab Essay

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I. Purpose The purpose of this lab is to find the equilibrium between an acid and a base. The point were at which all the acid has reacted with the base which will be indicated by a color change. I suspect that the average acetic acid percentage will be between 10-20% for part B of this experiment. II. Procedure Use a 10-mL graduated cylinder to put 6mL of 6 M sodium hydroxide solution (NaOH) into a clean 500mL storage bottle. Use a 100mL graduated cylinder to add 345mL of distilled water to the plastic bottle. Place a lid on the bottle and mix by shaking repeatedly. Sit the bottle off to the side for later use. Accurately weigh out three samples of potassium acid phthalate (KHP) with masses between 0.3-0.4g. Using an electronic balance, zero the balance, then place an empty container on the balance. Tare the balance so it reads zero with the empty container on the balance. Record the mass as zero. Add KHP to the container until the steady balance reading is between 0.3 and .04g more than the empty container. Record the mass then transfer the sample to a 125mL flask. Repeat the above steps to obtain a second and third sample. The samples don’t have to have the same mass as long as it’s between 0.3 and 0.4g. Add about 20mL of water and 3 drops of phenolphthalein indicator to each sample and allow the solid to dissolve. Prepare a 50mL buret for use by washing it, rinsing it with tap water, and rinsing it twice with distilled water. Finally rinse it twice with 5mL portions of your sodium hydroxide solution. Mount the buret on the ringstand and fill it above the zero mark with the prepared sodium hydroxide solution. Open the stopcock and allow the buret to drain until the liquid level is at zero. Make sure all the air bubbles are out of the tip of the buret. Read and record the intial buret reading to the 0.01mL. Place the 125mL flask containing the first KHP

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