Chemistry Lab Report PDF

Chemical Equations Results and Observations Acetone or Dimethyl Ketone, Solution of Iodine in Why would stearic acid be expected to show a lower Potassium Iodide, and Sodium Hydroxide...

Chemical Equations Results and Observations Acetone or Dimethyl Ketone, Solution of Iodine in Why would stearic acid be expected to show a lower Potassium Iodide, and Sodium Hydroxide solubility in water? CH3COCH3 + 3I2 + 4NaOH → CHI3 + CH3COONa + 3NaI + Stearic acid would be expected to show a lower solubility 3H2O in water because the solubility in water for carboxylic ○ Iodoform or Triiodomethane (CHI3) acids decreases when it has 5 carbon atoms and above. ○ Sodium Acetate (CH3COONa) Stearic acid has 18 carbon atoms, thus indicating a lower solubility in water compared to acetic acid with 2 carbon atoms and benzoic acid with 7 carbon atoms. EXPERIMENT 12: PROPERTIES OF CARBOXYLIC ACID AND SALICYLIC ACID Formula Carboxylic Acid Solubility in Water I. PURPOSE CH3COOH Acetic Acid Soluble To test the properties of carboxylic acid and salicylic acid C6H5COOH Benzoic Acid Slightly Soluble C17H35COOH Stearic Acid Insoluble II. APPARATUS Test Tubes, Test Tube Holder, Bunsen Burner, Clay Flame Shield, Wire Gauze, Beaker, Funnel, Mortar and Pestle III. MATERIALS Acetic Acid (CH3COOH) Benzoic Acid (C6H5COOH) Stearic Acid (C17H35COOH) Formic Acid (HCOOH) Oxalic Acid [(COOH)2] 0.5% Potassium Permanganate (KMnO4) Water Salicylic Acid (C6H4OHCOOH) Filter Paper B. ACTION OF AN OXIDIZING AGENT ON THE CARBONYL GROUP Ferric Chloride (FeCl3) Bromine Water (Br2 H2O) Place 5 drops of acetic, formic, benzoic acid, and oxalic acid in four Millon’s Reagent [Hg(NO3)2] separate test tubes and add 1 mL of 0.5% potassium permanganate Soda-Lime (NaOH CaO) to each tube. Heat the four test tubes in a water bath, and note if Methyl Alcohol (CH3OH) any reduction of the permanganate occurs. Conc. Sulfuric Acid (H2SO4) Results and Observations IV. PROCEDURES Carboxylic Before After Warm A. SOLUBILITY OF CARBOXYLIC ACID IN WATER Formula Acid Water Bath Water Bath Test the solubility in water of the following acids; acetic, benzoic, and Precipitate: Manganese (IV) Oxide stearic acid. Use 3 drops of liquid (or a pinch if solid) to 3 mL of Solution: HCOOH Formic Acid (MnO2) water. Account for the large observed differences in solubility Brown Color of Precipitate: between acetic acetic and stearic acid. Reddish-Brown Solution: (COOH)2 Oxalic Acid Solution: Colorless Orange 9  Carboxylic Before After Warm Formula Acid Water Bath Water Bath CH3COOH Acetic Acid No Reaction; Solution: Purple C6H5COOH Benzoic Acid Chemical Equation Salicylic Acid and Ferric Chloride 3C6H4OHCOOH + FeCl3 → Fe(C6H4OHCOO)3 + 3HCl ○ Ferric Salicylate [Fe(C6H4OHCOO)3] ○ Hydrochloric Acid (HCl) Chemical Equations REACTION WITH BROMINE WATER Formic Acid and 0.5% Potassium Permanganate HCOOH + KMnO4 + 6H+ → MnO2 + KOH + CO2 + H2O To the second five mL portion of the prepared solution, add a few drops of bromine water, a few drops at a time, until a light yellow ○ Precipitate: Manganese (IV) Oxide (MnO2) solution is obtained. Color: Reddish-Brown ○ Product of Oxidation: Carbon Dioxide (CO2) Results and Observations Oxalic Acid and 0.5% Potassium Permanganate (COOH)2 + KMnO4 + 6H+ → Mn2+ + KOH + CO2 + H2O Precipitate: 2,4,6-Tribromophenol ○ Precipitate: Manganese Ions (Mn2+) ○ Color: Yellowish ○ Color of Solution: Colorless ○ Product of Oxidation: Carbon Dioxide (CO2) C. PREPARATION OF SALICYLIC ACID SOLUTION Add 15 mL of water to 0.1 g of salicylic acid and shake the solution for a few minutes, filter the solution and divide the filtrate into three portions, and use them as stated below REACTION WITH FERRIC IONS To the first five mL portion of the prepared solution, add 1 or 2 drops of ferric chloride or ferric nitrate solution. Results and Observations Color of Solution: Violet 10 Chemical Equation Chemical Equation Salicylic Acid and Bromine Water Salicylic Acid and Soda-Lime C6H4OHCOOH + 2NaOH —CaO→ C6H5OH + Na2CO3 + H2O ○ Phenol (C6H5OH) ○ Sodium Carbonate (Na2CO3) —Br2 H2O→ ○ 2,4,6-Tribromophenol (C6H4OHBr3) E. ESTER FORMATION REACTION WITH MILLON’S REAGENT (MERCURIC NITRATE) Place in a test tube about 0.1 g of salicylic acid, add 15-20 drops of methyl alcohol and 1 mL of concentrated sulfuric acid, and gently To the last five mL portion of the solution prepared solution, add 1 or boil the mixture for 1-2 minutes: then pour the mixture into about 20 2 drops of Millon’s reagent, and warm the mixture. Observe the mL of water, contained in a beaker. Notice the odor of the diluted color of the precipitate. mixture. Results and Observations Results and Observations Precipitate: Mercuric Salicylate [Hg(C6H4OHCOO)2] Salicylic Acid + Methanol + Conc. Sulfuric Acid Odor: ○ Color: Reddish or Pink Minty or Oil of Winter Green Odor Chemical Equation Salicylic Acid, Methanol, and Conc. Sulfuric Acid C6H4OHCOOH + CH3OH —H2SO4→ C6H4OHCOOCH3 + H2O ○ Methyl Salicylate (C6H4OHCOOCH3) Chemical Equation Salicylic Acid and Millon’s Reagent (Mercuric Nitrate) 2C6H4OHCOOH + Hg(NO3)2 → Hg(C6H4OHCOO)2 + 2HNO3 ○ Mercuric Salicylate [Hg(C6H4OHCOO)2] ○ Nitric Acid (HNO3) D. DECARBOXYLATION: REACTION WITH SODA-LIME Grind in a mortar about 0.2 g of salicylic acid with 2 g of soda-lime, place the mixture in a dry test tube and heat strongly. Notice the odor of the vapors given off. Results and Observations Salicylic Acid + Soda-Lime Odor: Glue/Paste-like Odor 11  EXPERIMENTS 13-15 Chemical Equations EXPERIMENT 13: PREPARATION OF ASPIRIN Salicylic Acid and Acetic Anhydride C6H4OHCOOH + (CH3CO)2O → C6H4OCOCH3COOH + CH3COOH I. PURPOSE Acetylsalicylic Acid or Aspirin (C6H4OCOCH3COOH) Acetic Acid (CH3COOH) To conduct a chemical reaction to produce aspirin, to analyze the aspirin and estimate its purity. Values II. APPARATUS Weight of Dry Aspirin = 3.6 g Asp MWAsp = 180 g/mol MWSA = 138 g/mol Erlenmeyer Flask, Long Glass Tubing, Cork, Bunsen Burner, Clay MWAA = 102 g/mol Shield, Wire Gauze, Funnel dAA = 1.08 g/mL III. MATERIALS Theoretical Yield 3 g Salicylic Acid (C6H4OHCOOH) Limiting Reagent: Salicylic Acid 3 mL Acetic Anhydride [(CH3CO)2O] 3 Drops Conc. Sulfuric acid (H2SO4) Ice Bath (H2O) Filter Paper IV. PROCEDURES Percent (%) Yield A. PREPARATION OF ASPIRIN Place 3 grams of salicylic acid in a flask and add 3 mL of acetic anhydride. Add 3 drops of concentrated sulfuric acid and attach a long glass tubing with a cork (serves as an air condenser) and heat the flask in a water bath for 10 to 15 mins. Allow the flask to cool and EXPERIMENT 14: PROPERTIES OF ACETAMIDE AND UREA add about 30 mL of ice water. Crystallize the aspirin by cooling the flask in an ice bath. When the crystallization is complete, separate I. PURPOSE the aspirin crystals by filtration. Dry the crystals by pressing between filter papers. When sufficiently dry, get the weight of the aspirin crystals. To test and observe the properties of acetamide and urea through various tests Results and Observations II. APPARATUS Aspirin crystals formed Test Tubes, Test Tube Holder, Bunsen Burner, Clay Flame Shield, Wire Gauze, Breakers (100 mL, 400 mL, 600 mL), Stirring Rod III. MATERIALS Acetamide (CH3CONH2) 6 M Sodium Hydroxide (NaOH) Conc. Sulfuric Acid (H2SO4) Sodium Nitrate (NaNO2) Dry Urea (NH2CONH2) Conc. Nitric Acid (HNO3) Oxalic Acid [(COOH)2] 1  1% Cupric Sulfate (CuSO4) Results and Observations Dilute Sodium Hydroxide (NaOH) Dilute Hydrochloric Acid (HCl) Acetamide and Nitrous Acid (Sodium Nitrite and Conc. Ice (H2O) Sulfuric Acid) Red Litmus Paper ○ Gas Evolved: Nitrogen Gas (N2) ○ Formation of bubbles due to nitrogen gas (N2) IV. PROCEDURES ○ Organic Product: Acetic Acid (CH3COOH) A. BASE CATALYZED HYDROLYSIS Gently warm 0.5 grams of acetamide with 5 mL of 6 M sodium hydroxide solution. Prove the presence of ammonia. Pour 1 mL of the solution into a 100 mL beaker, add concentrated sulfuric acid in excess. Note the odor. Results and Observations Acetamide and Sodium Hydroxide ○ Gas Evolved: Ammonia Gas (NH3) Odor: Urine-like Odor Litmus Paper: Red → Blue ○ Organic Product: Sodium Acetate (CH3COONa) Chemical Equations Sodium Acetate and Conc. Sulfuric Acid ○ Organic Product: Acetic Acid (CH3COOH) Sodium Nitrite and Conc. Sulfuric Acid Odor: Vinegar-like Odor 2NaNO2 + H2SO4 → HNO2 + Na2SO4 Produced fumes ○ Nitrous Acid (HNO2) ○ Sodium Sulfate (Na2SO4) Chemical Equations Acetamide and Nitrous Acid CH3CONH2 + HNO2 → CH3COOH + N2 + H2O Acetamide and Sodium Hydroxide ○ Acetic Acid (CH3COOH) CH3CONH2 + NaOH → CH3COONa + NH3 ○ Nitrogen Gas (N2) ○ Sodium Acetate (CH3COONa) ○ Ammonia Gas (NH3) CHEMICAL PROPERTIES OF UREA Sodium Acetate and Conc. Sulfuric Acid 2CH3COONa + H2SO4 → 2CH3COOH + Na2SO4 C. FORMATION OF UREA NITRATE ○ Acetic Acid (CH3COOH) ○ Sodium Sulfate (Na2SO4) Dissolve ½ gram of urea in ½ mL of water. Add 2 drops of concentrated nitric acid to 2 drops of this solution. B. ACID CATALYZED HYDROLYSIS Results and Observations Dissolve 0.5 grams of acetamide in a few mL of water and add a solution of an equal weight of sodium nitrate in a little water. Organic Product: Urea Nitrate (NH2CONH2 HNO3) Prepare a solution of 6 drops of concentrated sulfuric acid in a few ○ Color of Precipitate: White Crystalline mL of water. Cool both solutions in an ice-bath and mix. Note the Reagent: Concentrated Nitric Acid (HNO3) production of a gas 2  Chemical Equations Urea and Saturated Oxalic Acid Solution NH2CONH2 + (COOH)2 → NH2CONH2 (COOH)2 ○ Urea Oxalate [NH2CONH2 (COOH)2] E. FORMATION OF BIURET Place 3 g of dry urea crystals in a pyrex tube and heat to high temperature. Observe. Then test the vapors evolved with the moist red litmus paper. Cool the test tube and examine residue. Results and Observations Chemical Equations Organic Product: Biuret (NH2CONHCONH2) Urea and Conc. Nitric Acid ○ Color of Precipitate: White Crystalline NH2CONH2 + HNO3 → NH2CONH2 HNO3 ○ Peptide Bond: CONH ○ Urea Nitrate (NH2CONH2 HNO3) Gas Evolved: Ammonia Gas (NH3) ○ Odor: Urine-like Odor ○ Litmus Paper: Red → Blue D. FORMATION OF UREA OXALATE Chemical Equations To 2 drops of the urea solution, add 2 drops of saturated oxalic solution. Urea and Heat NH2CONH2 → NH2CONHCONH2 + NH3 Results and Observations ○ Biuret (NH2CONHCONH2) ○ Ammonia Gas (NH3) Organic Product: Urea Oxalate [NH2CONH2 (COOH)2] ○ Color of Precipitate: White ○ Formation of bubbles F. BIURET TEST: TEST FOR PROTEINS Reagent: Saturated Oxalic Acid Solution [(COOH)2] Dissolve some of the residue from (3) in 4 ml of water. Add an equal amount of dilute NaOH solution and 1 drop of 1% cupric sulfate solution. Repeat the procedure using one g of unheated urea in 10 ml of water Results and Observations Biuret (Heated Urea), Water, Dil. Sodium Hydroxide, and Cupric Sulfate ○ Color of Solution: Purple/Pink (positive) ○ Easier to dissolve Unheated Urea, Water, Dil. Sodium Hydroxide, and Cupric Sulfate ○ Color of Solution: Blue (negative) Reagents: Dil. Sodium Hydroxide and 1% Cupric Sulfate 3  Chemical Equations Sodium Nitrite and Dil. Hydrochloric Acid NaNO2 + HCl → NaCl + HNO2 ○ Sodium Chloride (NaCl) ○ Nitrous Acid (HNO2) Urea and Nitrous Acid NH2CONH2 + HNO2 → N2 + H2CO3 ○ Nitrogen Gas (N2) ○ Carbonic Acid (H2CO3) Carbonic Acid and Heat H2CO3 → CO2 + H2O ○ Carbon Dioxide (CO2) Chemical Equations ○ Water (H2O) Biuret (Heated Urea), Water, Dil. Sodium Hydroxide, H. REACTION OF SODIUM HYDROXIDE ON UREA and Cupric Sulfate NH2CONHCONH2 + CuSO4 —NaOH→ NH2CONHCONH2 Place 1 g of urea in a test tube and add 3 ml of sodium hydroxide. CuSO4 Heat the solution to boiling point and test the vapors evolved with Unheated Urea, Water, Dil. Sodium Hydroxide, and moist litmus paper Cupric Sulfate NH2CONH2 + CuSO4 —NaOH→ No Reaction Results and Observations G. REACTIONS OF NITROUS ACID ON UREA Gas Evolved: Ammonia Gas (NH3) ○ Odor: Urine-like Odor Dissolve ½ g of urea in 5 ml of water. To this solution, add 3 ml of ○ Litmus Paper: Red → Blue dilute HCl and then 1-2 drops of NaNO2 Results and Observations Gasses Evolved ○ Nitrogen (N2): Small Bubbles ○ Carbon Dioxide (CO2): Bigger Bubbles Chemical Equations Urea and Sodium Hydroxide NH2CONH2 + 2NaOH → Na2CO3 + 2NH3 ○ Sodium Carbonate (Na2CO3) ○ Ammonia Gas (NH3) 4  Results and Observations ANILINE Aniline is a colorless liquid when freshly prepared, but changing in Aniline is a weak base therefore, red litmus paper did not time to dark brown or red, probably by the reason of oxidation. It change color. has a peculiar odor. Aniline is insoluble in water but soluble in Aniline and Water organic solvents. Aniline is quite toxic. One should not allow these ○ Organic Product: Anilinium Hydroxide compounds to stay on the skin and should avoid inhaling their ○ Color of Solution: Colorless vapors. Anilinium Hydroxide and Ferric Chloride ○ Organic Product: Anilinium Chloride or Aniline Hydrochloride EXPERIMENT 15: ANILINE ○ Color of Precipitate: Reddish-Brown I. PURPOSE To identify and understand the physical and chemical properties of aniline (aromatic amine) through its chemical reactions II. APPARATUS Test Tubes, Test Tube Holder, Bunsen Burner, Stirring Rod, Thermometer III. MATERIALS Aniline (C6H5NH2) Distilled Water (H2O) Chemical Equations Ferric Chloride (FeCl3) Concentrated Hydrochloric Acid (HCl) Aniline and Water Bromine Water (Br2 H2O) 5% Sodium Nitrite (NaNO2) Phenol (C6H5OH) Resorcinol [C6H4(OH)2] 8 N Sodium Hydroxide (NaOH) Anilinium Hydroxide and Ferric Chloride Ice Bath (H2O) Red and Blue Litmus Paper IV. PROCEDURE B. SALT FORMATION A. BASICITY Mix ½ mL of aniline with a slight excess of concentrated HCI Shake a drop of aniline with 2 mL of distilled water and test the Observe the change in color solution with litmus paper. Observe. To one half of the solution add a few drops of ferric chloride solution. Note the color Results and Observations Separation of Layers ○ Upper: White Salt Ring of Anilinium Chloride Crystals ○ Bottom: Brown Solution Organic Product: Anilinium Chloride or Aniline Hydrochloride 5  Chemical Equations Aniline and Bromine Water D. DIAZOTIZATION Chemical Equations Place 2 mL of aniline in a test tube, add 10 ml of water and 4 mL of Aniline and Hydrochloric Acid concentrated HCI. Shake and cool to 0°C in an ice bath, then add 1 mL cold solution (0°C) of 5% NaNO2 solution. Keep the mixture in the ice bath and save for (E) and (F). The resulting solution should be colorless. Results and Observations Color of Solution: Nearly Colorless, with Brown Tinge ○ Should be colorless C. EFFECT OF NH2 GROUP ON SUBSTITUTION IN THE BENZENE RING Organic Product: Benzenediazonium chloride Add bromine water dropwise with shaking to a mixture of 3 drops of aniline and 2 ml of water. Results and Observations Color of Solution: Clear Yellow ○ Should be White to Pinkish Formation of insoluble globules of bromine (Br2) Organic Product: 2,4,6-tribromoaniline Chemical Equations Aniline, Water, Conc. Hydrochloric Acid, and 5% Sodium Nitrite 6  E. FORMATION OF PHENOL Results and Observations Take ¼ of the cold diazotized aniline from (D) and warm gently. Phenol Observe the behavior of the mixture and the resulting odor after ○ Organic Product: Benzeneazo-phenol or the reaction has subsided. p-Hydroxyazobenzene ○ Color of Precipitate: Bright Yellow Results and Observations ○ Color of Solution: Yellow Resorcinol Organic Product: Phenol (C6H5OH) ○ Organic Product: Benzeneazo-resorcinol or ○ Odor: Paste-like Odor 2,4-dihydroxyazobenzene ○ Color: Reddish/Pinkish ○ Color of Precipitate: Bright Orange Gas Evolved: Nitrogen Gas (N2) ○ Color of Solution: Orange Chemical Equations Chemical Equations Benzenediazonium Chloride and Heat Phenol, 8 N Sodium Hydroxide, and Benzenediazonium Chloride F. COUPLING AND FORMATION OF DYES Resorcinol, 8 N Sodium Hydroxide, and Benzenediazonium Chloride Be careful not to allow any of the compounds made in this experiment to get on the desk or hands. In two test tubes, place separately 1 mL of phenol and resorcinol solutions. Add to each 3 drops of 8 N NaOH solution, then 1 ml. of the diazotized aniline from (D). Shake well. Observe. Add 15-20 mL of water to each test tube and shake it again. 7