Experiment 2 - Lab Report PDF

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-----------Lab Partner – ---------9/13/2018, CHEM 3105TA – Experiment 2 – Separation of a Mixture of Carboxylic Acid and a Hydrocarbon Purpose: To purify and separate the mixture containing the carboxylic acid and a hydrocarbon. Reaction & Physical Properties Table: Species

MW (g/mol)

Densit y (g/mL)

b.P. (Celcius)

Amount (mL)

Weight (g)

Moles (gmol)

Benzoic

122.12 3

1.3

249.2

O-Chlorobenzoic Acid

156.56 5

1.544

Naphtalene

128.17 4

1.16

218

Biphenyl

154.21 2

1.041

256

Diethyl Ether

74.123

0.713

35

30

21.39

3.465

2 M NaOH (aq)

39.997

2.13

1388

5

10.5

3.809

6 M HCL (aq)

36.458

1.19

-85.05

2

2.38

15.318

Saturated NaCl (aq)

58.440

2.17

1465

10

21.7

2.693

Hydroxide Benzoic Acid

Proton Benzoate

Benzoate

Benzoic Acid

Naphthalene

Biphenyl

O-Chlorobenzoic Acid

Safety: Benzoic Acid  Risk Statements: o Harmful if Swallowed o Causes Skin Corrosion/Irritation o Causes Serious Eye Damage/Eye Irritation o Causes Damage to Organs O-Chlorobenzoic Acid  Risk Statements: o Harmful if Swallowed o Causes Skin Corrosion/Irritation o Causes Serious Eye Irritation/Damage Naphthalene  Risk Statements: o Flammable Solid o Harmful if Swallowed o Suspected Carcinogen o Very Toxic to Aquatic Life with Long Lasting Effects Biphenyl  Risk Statements: o Causes Serious Skin Corrosion/Irritation o Causes Serious Eye Irritation, Fatal if Inhaled o Causes Respiratory Irritation o Very Toxic to Aquatic Life with Long Lasting Effects Diethyl Ether  Risk Statements: o Extremely Flammable Liquid and Vapor o Harmful if Swallowed o May cause dizziness or drowsiness Sodium Hydroxide  Risk Statements: o May be Corrosive to Metals o Causes Server Skin Burns and Eye Damage Hydrochloric Acid  Risk Statements: o May be Corrosive to Metals o Causes Server Skin Burns and Eye Damage o Toxic if Inhaled o May Cause Respiratory Irritation Sodium Chloride  Risk Statements:

o May Cause Skin Irritation o Causes Irritation to Eyes In case of contact with eyes, remove contact lenses if present and flush eyes at eye wash station for 20 to 30 minutes. In case of inhalation, immediately leave the contaminated area and take deep breaths of fresh, uncontaminated air. In case of contact with skin, immediately flood the affected skin with water and remove and isolate the contaminated clothing. In case of ingestion, immediately drink 1-2 glasses of water to dilute the chemical and immediately call poison control. Protocol: 1. Get about 0.5 g of one of the unknown mixture samples. Record the actual mass and your unknown’s number. 2. Add 20 mL of diethyl ether to the separatory funnel with it closed. Add your sample. Stir until it is completely dissolves. 3. lowly add 5 mL of cold 2M NaOH to the separatory funnel, put in the stopper, and mix the two layers together. Vent the separatory funnel frequently. Expect a positive pressure in your separatory funnel. 4. Place the separatory funnel in an iron ring and allow the two layers to separate. 5. Use pH paper to make sure that the aqueous solution is basic. Use a stirring rod to reach through the top opening to the aqueous layer and then touch it to a piece of pH paper. If the aqueous layer is not basic, add 1-2 mL of 2 M NaOH, mix it, and then check again. 6. Leave the separatory funnel in an iron ring until the two layers separate completely. 7. Determine which layer is the aqueous phase and which layer is the organic phase. Remove the stopper from the separatory funnel. Drain the layers into small labeled Erlenmeyer flasks or beakers. Label the organic layer as "Ether". Label the basic aqueous as "Basic Water". 8. Return the aqueous layer to the separatory funnel and wash it again with diethyl ether (10 mL). Separate the layers again and combine the organic solutions in the container labeled "Ether". Drain the water layer into the "Basic water" container. 9. Since water is partially soluble in the diethyl ether layer, it needs to be removed in two stages. Mixing the solution with a saturated NaCl solution will draw out part of the water dissolved in the diethyl ether solution. To do this return the diethyl solution to the separatory funnel and add 10 mL of saturated NaCl (aq) solution. Mix and allow to separate. Drain the organic layer into a clean dry flask or beaker appropriate for the volume of liquid. Keep the aqueous brine solution in a separate container until you are absolutely sure you know which layer the organic diethyl ether layer is and which is the aqueous layer. 10. Finish drying the diethyl ether solution by adding small amounts (cover the tip of your scoopula) anhydrous MgSO4 with mixing until the some of the solid MgSO4 remains free-flowing when swirled. 11. Pack a conical funnel with a small piece of cotton using your finger tip to push it into the narrow opening of the stem inside the funnel. Packed cotton is sufficient to filter the

MgSO4 drying agent from an organic layer and is faster than using filter paper. You can now pour your solution into the funnel and allow the solution to filter through the cotton into a clean dry beaker. The filtered diethyl ether solution should be completely free of powder after filtration before moving to the next step. 12. Remove the solvent from the diethyl ether solution in the hood by using compressed air to gently evaporate the diethyl ether. 13. The solid material recovered after the evaporation of the diethyl ether solution needs to be saved for Experiment 3. Weigh an empty shell vial and note the weight in your lab notebook. Using a spatula to gently scrape solid from the beaker and transfer the solution into the vial. Weigh the vial again. Note the weight of the vial with the solid in your notebook and take the difference of weights to get the amount of solid recovered. Cap the vial and label it. 14. Add 2 mL of 6 M HCl to the container labeled Basic aq and gently mix by swirling or stirring with your stirring rod. Check the pH of the solution to confirm the pH is 1-2. A solid should precipitate from the solution. 15. Collect the solid by filtration using a Hirsch funnel (small) or Buckner funnel (large) depending on how much solid precipitated from the aqueous solution. Gently swirl the container with the precipitation to get it suspended before pouring the mixture into the funnel. Rinse any remaining solid from the container into the filter funnel using 5-10 mL of cold water. 16. The solid collected in the filter funnel needs to be saved for Experiment 3. 17. The aqueous filtrate in your filter flask should be disposed of in the aqueous acid waste. Data & Observation: 0.512 grams of Unknown #2 – 30 mL of Diethyl Ether – 20 mL of Sodium Hydroxide 9 mL 6 M Hydrochloric Acid – 0.188 grams Final Weight of Hydrocarbon Calculations & Results: See above (Not Applicable) Post Lab Questions: 1. Why is sodium benzoate more soluble in water than benzoic acid? The sodium benzoate dissolves in water more readily than benzoic acid. This is caused by the ionic bond between the sodium ion. The positive sodium ion is attached to the negative end of the water molecules, the oxygen, and the negatively charged carboxyl group is now attracted to the positive end in the water molecules (the hydrogen). The sodium benzoate is a very polar molecule and easily soluble in the polar solvent water because of this. 2. Why is biphenyl more soluble in diethyl ether than water?

The Biphenyl does not dissolve in water because it is a non-polar compound and because of the absence of hydrogen bonding. Glucose is soluble in water and insoluble in diethyl ether because of this. 3. What solvent (diethyl ether or water) would glucose be most soluble in? Why? Glucose is an organic molecule that has several places capable of hydrogen bonding and contains a lot of polar bonds. This is because the glucose is very soluble in water and is thus insoluble in diethyl ether. 4. Outline a procedure for separating anthracene and indoline using extraction and possible acid/base chemistry. You need to add the mixture to the separatory funnel to begin the extraction first to separate the anthracene and indoline. The anthracene is insoluble in water and the indoline is soluble in warm water. Then add warm water to the mixture and shake. Then allow the mixture to settle. You should see two layers formed. Anthracene is denser than the water and indoline. This means it will be at the bottom. Carefully open the drain of separatory funnel and allow the anthracene to drain out. Be careful not to allow any of the water/indoline layer to drain out. This solution should now be pure anthracene. Separate the indoline from the water/indoline solution is needed. Water has a boiling point of 100 degrees Celsius and indoline has a boiling point of 253 degrees Celsius. The simple distillation of the water/indoline mixture should result in separate solutions of water and indoline. Works Cited National Center for Biotechnology Information. PubChem Compound Database; CID=243, https://pubchem.ncbi.nlm.nih.gov/compound/243 (accessed Sept. 12, 2018). National Center for Biotechnology Information. PubChem Compound Database; CID=313, https://pubchem.ncbi.nlm.nih.gov/compound/313 (accessed Sept. 12, 2018). National Center for Biotechnology Information. PubChem Compound Database; CID=931, https://pubchem.ncbi.nlm.nih.gov/compound/931 (accessed Sept. 12, 2018). National Center for Biotechnology Information. PubChem Compound Database; CID=3283, https://pubchem.ncbi.nlm.nih.gov/compound/3283 (accessed Sept. 12, 2018). National Center for Biotechnology Information. PubChem Compound Database; CID=5234, https://pubchem.ncbi.nlm.nih.gov/compound/5234 (accessed Sept. 12, 2018). National Center for Biotechnology Information. PubChem Compound Database; CID=7095, https://pubchem.ncbi.nlm.nih.gov/compound/7095 (accessed Sept. 12, 2018). National Center for Biotechnology Information. PubChem Compound Database; CID=8374, https://pubchem.ncbi.nlm.nih.gov/compound/8374 (accessed Sept. 12, 2018). National Center for Biotechnology Information. PubChem Compound Database; CID=14798, https://pubchem.ncbi.nlm.nih.gov/compound/14798 (accessed Sept. 12, 2018)....