Question

Explain how the following would affect the concentration of NaOH from part I and molar mass of H2X from part II. a. Over-titration in Part I, adding too much hydroxide to the titration flask. b. Over-titration in Part II, adding too much hydroxide to the titration flask. c. KHP was not properly dry due to improper storage out of a desiccator. d. A student leaves their funnel propped at the top of the buret during the part I titration. After the initial volume is read, the buret is jostled, causing an extra few drops of NaOH to fall from the funnel into the buret. e. Suppose the titrations in Part I and Part II were conducted on different days. After your part I titration, the NaOH solution was allowed to sit out on the bench where it is exposed to CO2 in the atmosphere. (Hint: CO2(g) + H2O(l) → H2CO3(aq)) f. H2X turns out to be strongly hygroscopic, but was never stored in a desiccator. Procedure Part I: Standardization of NaOH Solution In this first part, a ready-made solution of sodium hydroxide will be titrated against KHP so as to determine the concentration of the hydroxide in solution. All waste from the portion of the lab may be washed into the sink with plenty of cold water. You will not work with lab partners during this lab. All lab steps will be completed by each student individually. 1. Fill a beaker with ~200 mL of DI water and bring the water to ~60°C on a hot plate. 2. Remove the beaker from heat as soon as the desired temperature is reached. 3. Weigh out ~0.30 g KHP and pour it into a clean Erlenmeyer flask. 4. Add ~50 mL of your heated DI water to the KHP flask, then swirl until the KHP is fully dissolved. 5. Add ~2 drops of phenolphthalein indicator to the KHP flask. 6. Allow the flask to cool to room temperature before continuing. 7. Record the initial volume of hydroxide contained within your buret. 8. With your KHP flask underneath your buret, open the buret to allow hydroxide into the flask. 9. Continue to add hydroxide to your KHP flask until the pink color can no longer be shaken away. This marks the end point of your titration. 10. Rinse the tip of your buret into the KHP flask with DI water. 11. Record the final volume of the buret. 12. Calculate the molarity of your hydroxide and report your data to the class google sheet using one of the laptops set up in the lab. 13. Record the class average molarity for the hydroxide solution. Part II: Titration of a Diprotic Acid Now that you've standardized the hydroxide solution, this solution can be used in additional titrations. You will be given an unknown diprotic acid and asked to determine its molar mass. This can be done by titrating a known mass of the acid so as to determine the moles contained within that mass. Weight out ~0.11 g of the unknown diprotic acid, record the exact mass used, and repeat the titration procedure used in Part I, replacing KHP with the unknown acid. Ensure that you have at least 25 mL of hydroxide in your buret before beginning a titration.

Name: explain how the following would affect the concentration of naoh from part i and molar mass of h2x from part ii a over titration in part i adding too much hydroxide to the titration flask b 93123
Uploaded: 2022-11-17T22:57:26-08:00
Duration: 2 min 17 s
Channel: Sri K
Description: explain how the following would affect the concentration of naoh from part i and molar mass of h2x from part ii a over titration in part i adding too much hydroxide to the titration flask b 93123

Explain how the following would affect the concentration of NaOH from part I and molar mass of H2X from part II.

a. Over-titration in Part I, adding too much hydroxide to the titration flask.
b. Over-titration in Part II, adding too much hydroxide to the titration flask.
c. KHP was not properly dry due to improper storage out of a desiccator.
d. A student leaves their funnel propped at the top of the buret during the part I titration. After the initial volume is read, the buret is jostled, causing an extra few drops of NaOH to fall from the funnel into the buret.
e. Suppose the titrations in Part I and Part II were conducted on different days. After your part I titration, the NaOH solution was allowed to sit out on the bench where it is exposed to CO2 in the atmosphere. (Hint: CO2(g) + H2O(l) → H2CO3(aq))
f. H2X turns out to be strongly hygroscopic, but was never stored in a desiccator.

Procedure Part I: Standardization of NaOH Solution

In this first part, a ready-made solution of sodium hydroxide will be titrated against KHP so as to determine the concentration of the hydroxide in solution. All waste from the portion of the lab may be washed into the sink with plenty of cold water. You will not work with lab partners during this lab. All lab steps will be completed by each student individually.

1. Fill a beaker with ~200 mL of DI water and bring the water to ~60°C on a hot plate.
2. Remove the beaker from heat as soon as the desired temperature is reached.
3. Weigh out ~0.30 g KHP and pour it into a clean Erlenmeyer flask.
4. Add ~50 mL of your heated DI water to the KHP flask, then swirl until the KHP is fully dissolved.
5. Add ~2 drops of phenolphthalein indicator to the KHP flask.
6. Allow the flask to cool to room temperature before continuing.
7. Record the initial volume of hydroxide contained within your buret.
8. With your KHP flask underneath your buret, open the buret to allow hydroxide into the flask.
9. Continue to add hydroxide to your KHP flask until the pink color can no longer be shaken away. This marks the end point of your titration.
10. Rinse the tip of your buret into the KHP flask with DI water.
11. Record the final volume of the buret.
12. Calculate the molarity of your hydroxide and report your data to the class google sheet using one of the laptops set up in the lab.
13. Record the class average molarity for the hydroxide solution.

Part II: Titration of a Diprotic Acid

Now that you've standardized the hydroxide solution, this solution can be used in additional titrations. You will be given an unknown diprotic acid and asked to determine its molar mass. This can be done by titrating a known mass of the acid so as to determine the moles contained within that mass.

Weight out ~0.11 g of the unknown diprotic acid, record the exact mass used, and repeat the titration procedure used in Part I, replacing KHP with the unknown acid. Ensure that you have at least 25 mL of hydroxide in your buret before beginning a titration.

Added by Sebastian S.

Chemistry: Structure and Properties

Nivaldo Tro 2nd Edition

Instant Answer

Solved by Expert Sri K

11/17/2022

Step 1

This is because the volume of NaOH required to reach the endpoint would be more than necessary, leading to an overestimation of the concentration of NaOH. ** Show more…

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Explain how the following would affect the concentration of NaOH from part I and molar mass of H2X from part II. a. Over-titration in Part I, adding too much hydroxide to the titration flask. b. Over-titration in Part II, adding too much hydroxide to the titration flask. c. KHP was not properly dry due to improper storage out of a desiccator. d. A student leaves their funnel propped at the top of the buret during the part I titration. After the initial volume is read, the buret is jostled, causing an extra few drops of NaOH to fall from the funnel into the buret. e. Suppose the titrations in Part I and Part II were conducted on different days. After your part I titration, the NaOH solution was allowed to sit out on the bench where it is exposed to CO2 in the atmosphere. (Hint: CO2(g) + H2O(l) → H2CO3(aq)) f. H2X turns out to be strongly hygroscopic, but was never stored in a desiccator. Procedure Part I: Standardization of NaOH Solution In this first part, a ready-made solution of sodium hydroxide will be titrated against KHP so as to determine the concentration of the hydroxide in solution. All waste from the portion of the lab may be washed into the sink with plenty of cold water. You will not work with lab partners during this lab. All lab steps will be completed by each student individually. 1. Fill a beaker with ~200 mL of DI water and bring the water to ~60°C on a hot plate. 2. Remove the beaker from heat as soon as the desired temperature is reached. 3. Weigh out ~0.30 g KHP and pour it into a clean Erlenmeyer flask. 4. Add ~50 mL of your heated DI water to the KHP flask, then swirl until the KHP is fully dissolved. 5. Add ~2 drops of phenolphthalein indicator to the KHP flask. 6. Allow the flask to cool to room temperature before continuing. 7. Record the initial volume of hydroxide contained within your buret. 8. With your KHP flask underneath your buret, open the buret to allow hydroxide into the flask. 9. Continue to add hydroxide to your KHP flask until the pink color can no longer be shaken away. This marks the end point of your titration. 10. Rinse the tip of your buret into the KHP flask with DI water. 11. Record the final volume of the buret. 12. Calculate the molarity of your hydroxide and report your data to the class google sheet using one of the laptops set up in the lab. 13. Record the class average molarity for the hydroxide solution. Part II: Titration of a Diprotic Acid Now that you've standardized the hydroxide solution, this solution can be used in additional titrations. You will be given an unknown diprotic acid and asked to determine its molar mass. This can be done by titrating a known mass of the acid so as to determine the moles contained within that mass. Weight out ~0.11 g of the unknown diprotic acid, record the exact mass used, and repeat the titration procedure used in Part I, replacing KHP with the unknown acid. Ensure that you have at least 25 mL of hydroxide in your buret before beginning a titration.