UST General Santos Activity 3: Characteristic Reactions of Hydrocarbons PDF

PRAYER BEFORE CLASS Holy Spirit, Divine Creator, true source of light and fountain of wisdom! Pour forth your brilliance upon my dense intellect, dissipate the darkness which covers me, that of sin and of ignorance. Grant me a penetrating mind to understand, a retentive memory, method and ease of le...

PRAYER BEFORE CLASS Holy Spirit, Divine Creator, true source of light and fountain of wisdom! Pour forth your brilliance upon my dense intellect, dissipate the darkness which covers me, that of sin and of ignorance. Grant me a penetrating mind to understand, a retentive memory, method and ease of learning, the lucidity to comprehend, and abundant grace in expressing myself. Guide the beginning of my work, direct its progress and bring it to successful completion. This I ask through Jesus Christ, true God, and true man, living and reigning with You and the Father, forever and ever. Amen.  UST General Santos Activity 3: Characteristic Reactions of Hydrocarbons Inorganic and Organic Chemistry Laboratory Unit Intended Learning Outcome: At the end of the unit, the student must be able to differentiate hydrocarbons in terms of: a. intrinsic physical properties; b. chemical properties, structure, and behavior characterize hydrocarbons based on: a. flammability; b. active unsaturation; c. aromaticity Topic Outline ❖ Properties of Hydrocarbons Physical Properties Chemical Properties ❖ Laboratory Procedures Physical Characteristics Solubility in Concentrated H2SO4 Ignition Test Test for Active Unsaturation Test for Aromaticity: Nitration Test Test for Basic Oxidation  UST General Santos Properties of Hydrocarbons Characteristic Reactions of Hydrocarbons Physical Properties of Hydrocarbons 1. Solubility 2. Density 3. Boiling Point Physical Properties of Hydrocarbons Solubility - insoluble in water - soluble in nonpolar Density - water: 1.0 g/mL - alkanes, alkenes, alkynes: lower density than water - increases with increasing number of carbon atoms Physical Properties of Hydrocarbons Boiling Point of Alkanes and Alkenes 30C Carbon atom - alkanes with branching on a carbon chain - lower boiling point - cycloalkanes - higher boiling point than noncyclic counterpart Physical Properties of Hydrocarbons Boiling Point of Alkynes Molecular Weight Boiling Point Physical Properties of Hydrocarbons - short continuous chain alkanes (1-4 carbon atoms) - gases at room temperature - continuous chain alkanes (5-17 carbon atoms) - liquids at room temperature - longer than 17 carbon atoms chain alkanes - solids at room temperature Physical Properties of Hydrocarbons - alkenes with 2-4 carbon atoms - gases at room temperature - unsubstituted alkenes with 5-17 carbon atoms and one double bond - liquids at room temperature - alkenes with more than 17 carbon atoms - solids at room temperature Physical Properties of Hydrocarbons - low molecular mass alkyne - gases at room temperature - benzene (aromatic hydrocarbon) - liquids at room temperature Chemical Properties of Hydrocarbons Combustion - reaction between a substance and oxygen (usually from air) that proceeds with the evolution of heat and light CxHx + O2 CO2 + H2O + Heat Energy Chemical Properties of Hydrocarbons Combustion COMPLETE INCOMPLETE Combustion Combustion CxHx + O2 CO2 + H2O CxHx + O2 CO + H2O Chemical Properties of Hydrocarbons ALKANES & ALKENES & AROMATIC ALKYNES HYDROCARBON Single Bond → Sigma Bond Double/Triple Bonds → Pi Bond Stable and Strong Unstable ✅ Substitution Reaction ✅ Addition Reaction Chemical Properties of Alkanes and Cycloalkanes Halogenation - chemical reaction between a substance and a halogen in which one or more halogen atoms are incorporated into molecules of the substance Chemical Properties of Alkanes and Cycloalkanes Halogenation - chemical reaction between a substance and a halogen in which one or more halogen atoms are incorporated into molecules of the substance Chemical Properties of Alkenes and Cycloalkenes Hydrogenation - Addition reaction in which H2 is incorporated into molecules of an organic compound Chemical Properties of Alkenes and Cycloalkenes Halogenation - Addition reaction in which a halogen is incorporated into molecules of an organic compound Chemical Properties of Alkenes and Cycloalkenes Hydrohalogenation - addition reaction in which a hydrogen halide (HCl, HBr or HI) is incorporated into molecules of an organic compound Chemical Properties of Alkenes and Cycloalkenes Hydration - addition reaction in which H2O is incorporated into molecules of an organic compound Chemical Properties of Alkenes and Cycloalkenes Polymerization - alkene molecules undergo an addition reaction with one another Chemical Properties of Alkynes Addition Reaction Chemical Properties of Aromatic Hydrocarbons Alkylation Chemical Properties of Aromatic Hydrocarbons Halogenation  UST General Santos Procedures Characteristic Reactions of Hydrocarbons Instructions ❖ Please refer to pages 37-39 for the materials needed and specific procedure of the activity. Materials needed ❖ Red and blue litmus paper ❖ Beaker ❖ Test tubes ❖ Evaporating dish ❖ Erlenmeyer flask ❖ Pasteur pipettes ❖ Thermometer A. Physical Characteristics 1. Describe the physical appearance of the sample at room temperature. A. Physical Characteristics 2. Place 5 drops of the sample on a 5 drops of the watch glass. Take note of the time it sample takes for the sample to completely evaporate *if sample has not evaporated after 15 minutes, describe the sample as “non-volatile” B. Solubility in Concentrated H2SO4 1. In a test tube, carefully introduce 10-16 drops of conc. H2SO4 10-15 drops 1 drop 2. Add 1 drop of the sample of Conc H2SO4 of the sample into the test tube 3. Note any color or temperature change in the mixture PRECAUTION: Conc. H2SO4 is CORROSIVE. It is dehydrating and may react with water violently. WASTE DISPOSAL: NEUTRALIZE the solution in the test tube with ~2 mL 10% NaOH and place the solution in the waste bottle provided. C. Ignition Test 1. Place 5 drops of the sample in a small evaporating dish 2. Apply a lighted match to the sample 5 drops 3. Note the color of the flame of the sample and the residue D. Tests for Active Unsaturation BAEYER’S TEST 1. Place 5 drops of the sample into a test tube 2. Add 2 drops of 2% KMnO4 into the 5 drops 2 drops of the sample of 2% KMnO4 test tube 3. Shake the mixture vigorously and observe the rate and extent of color change in the reagent D. Tests for Active Unsaturation BAEYER’S TEST 4. Record rate as “immediate color change” if the color change occurred in less than a minute. otherwise, record 5 drops 2 drops of the sample of 2% KMnO4 “slow color change” 5. Record the extent of color change as initial to final color of the solution 6. As negative control, repeat steps 1-3 using water as the sample D. Tests for Active Unsaturation BROMINE TEST 1. Place 5 drops of the sample into a test tube 2. Add 10 drops of 0.5% BR2 in CCl4 5 drops 10 drops of the sample of 0.5% CCl4 into the test tube 3. Shake the mixture vigorously and observe the rate and extent of color change in the reagent D. Tests for Active Unsaturation BROMINE TEST 4. Record rate as “immediate color change” if the color change occurred in less than a minute. otherwise, record 5 drops 10 drops of the sample of 0.5% CCl4 “slow color change” 5. Record the extent of color change as initial to final color of the solution 6. If after 1 minute, there is still no color change, expose the solution to sunlight E. Test for Aromaticity: Nitration Test 2 mL conc. HNO3 1. Place 2 mL of conc. HNO3 in an erlenmeyer flask. Immerse the flask in an evaporating dish containing water PRECAUTION: Conc. HNO3 is CORROSIVE and OXIDIZING. WASTE DISPOSAL: Place the solutions and the nitrating mixture in a large beaker and slowly dilute with 20 mL water. Add small amounts of sodium carbonate (Na2CO3) until foaming ceases and place in the appropriate waste bottle  2 mL conc. H2SO4 E. Test for Aromaticity: Nitration Test 2 mL conc. HNO3 2. Gradually add 2 mL of conc. H2SO4 into the flask. Cool the resulting mixture to room temperature. This mixture serves as the nitrating mixture. PRECAUTION: Conc. H2SO4 is CORROSIVE. It is dehydrating and may react with water violently. WASTE DISPOSAL: Place the solutions and the nitrating mixture in a large beaker and slowly dilute with 20 mL water. Add small amounts of sodium carbonate (Na2CO3) until foaming ceases and place in the appropriate waste bottle E. Test for Aromaticity: Nitration Test 3. Place 5 drops of the sample in a test tube. Add 8 drops of the nitrating mixture and mix. Observe the formation of a yellow oily layer. Dilute the mixture with 20 drops of water. 5 drops 8 drops 20 drops of the sample nitrating mixture water WASTE DISPOSAL: Place the solutions and the nitrating mixture in a large beaker and slowly dilute with 20 mL water. Add small amounts of sodium carbonate (Na2CO3) until foaming ceases and place in the appropriate waste bottle E. Test for Aromaticity: Nitration Test 4. If there is no apparent reaction observed within 1 min., place the test tube in a water bath (~50C) for 10 20 drops mins. Dilute again with 20 drops of water water WASTE DISPOSAL: Place the solutions and the nitrating mixture in a large beaker and slowly dilute with 20 mL water. Add small amounts of sodium carbonate (Na2CO3) until foaming ceases and place in the appropriate waste bottle  5 drops sample F. Test for Basic Oxidation 8 drops 1. Place 5 drops of the sample in a test tube 2% KMnO4 2. Add 8 drops of 2% KMnO4 (aq) and 3 drops of 10% NaOH (aq) to the sample 3 drops 3. Shake the mixture vigorously and observe the 10% NaOH (aq) rate and extent of color change of the sample  5 drops sample F. Test for Basic Oxidation 8 drops 4. Record rate as “immediate color change” if the 2% KMnO4 color change occurred in less than 1 min. Otherwise, record “slow color change” 3 drops 5. Record the extent of color change as initial to 10% NaOH (aq) final color of the solution  UST General Santos Activity 3: Characteristic Reactions of Hydrocarbons Inorganic and Organic Chemistry Laboratory References ❖ Bettelheim, F. A, W. H., Brown, M. K. Campbell, S. O. Farrell & O. Torres. (2021). Introduction to General, Organic and Biochemistry, 12th ed. Boston, MA, USA: Cengage Learning End of discussion Do you have any questions? PRAYER AFTER CLASS Grant me, O Lord my God, a mind to know you, a heart to seek you, wisdom to find you, conduct pleasing to you, faithful perseverance in waiting for you, and a hope of finally embracing you, Amen.