ORGANIC CHEMISTRY 1 1 ALKANES LEARNING OBJECTIVES TO

ORGANIC CHEMISTRY 1. 1 ALKANES LEARNING OBJECTIVES: TO UNDERSTAND THE STRUCTURE AND NOMENCLATURE OF ALKANES. KEY WORDS: • • ORGANIC COMPOUNDS HYDROCARBON SATURATED HYDROCARBON ALKANE

ORGANIC COMPOUNDS

ORGANIC COMPOUNDS STUDY OF CARBON COMPOUNDS. THE EXCEPTIONS ARE: CO(G) (CARBON MONOXIDE), CO 2 (CARBON DIOXIDE) AND HCN (HYDROGEN CYANIDE). H: 0. 9% TI: 0. 6% OTHERS: 0. 9% C IS ONE OF THE 116 ELEMENTS

ORGANIC COMPOUNDS ISOLATION FROM NATURE (ANIMAL AND PLANT (EXTRACT-ISOLATE-PURIFY) OBTAINED BY: SYNTHESIS IN LAB ORGANIC COMPOUNDS: 10 MILLION INORGANIC COMPOUND: 1. 7 MILLION COMPOUNDS IN LIVING SYSTEMS ARE ORGANIC: BIOCHEMISTRY

ORGANIC COMPOUNDS FIRST ORGANIC COMPOUND THAT IS SYNTHESIZED IN LAB BY A GERMAN CHEMIST.

ORGANIC COMPOUNDS TYPICAL ORGANIC COMPOUNDS: • CONTAIN CARBON • HAVE COVALENT BONDS • HAVE LOW MELTING POINTS • HAVE LOW BOILING POINTS • ARE FLAMMABLE (ALL BURN) • ARE SOLUBLE IN NONPOLAR SOLVENTS • MAY BE GASES, LIQUIDS OR SOLIDS C 3 H 8 PROPA NE

– Carbon: normally forms four covalent bonds and has no unshared pairs of electrons. C – Hydrogen: forms one covalent bond and no unshared pairs of electrons. H – Nitrogen: normally forms three covalent bonds and has one unshared pair of electrons. N. . – Oxygen: normally forms two covalent bonds and has two unshared pairs of electrons. . O. = – Halogen: normally forms one covalent bond and has three unshared. . pairs of electrons. . . CL. .

TASK DRAW LEWIS STRUCTURES FOR THE FOLLOWING: H 2 O 5 MINUTES CH 4 CO 2 END

FUNCTIONAL GROUPS AN ATOM OR GROUP OF ATOMS WITHIN A MOLECULE THAT SHOWS A CHARACTERISTIC SET OF PREDICTABLE PHYSICAL AND CHEMICAL PROPERTIES. – A WAY TO CLASSIFY ORGANIC COMPOUNDS INTO FAMILIES. – THEY DETERMINE THE CHEMICAL AND PHYSICAL PROPERTIES OF A COMPOUND. – THEY UNDERGO THE SAME TYPES OF CHEMICAL REACTIONS. – A WAY TO NAME ORGANIC COMPOUNDS.

HYDROCARBONS LARGE FAMILY OF ORGANIC COMPOUNDS COMPOSED OF ONLY CARBON AND HYDROGEN SATURATED HYDROCARBONS UNSATURATED HYDROCARBON ALKANES C-C ALKENES, ALKYNES & AROMATI C=C C C

CARBON • CARBON HAS FOUR VALENCE ELECTRONS; HYDROGEN HAS ONE. • • C • H • • • TO OBTAIN AN OCTET, CARBON FORMS FOUR BONDS. H • • H H H CH 4 , METHANE

Crash. Course - Hydrocarbons

ALKANES

METHANE TETRAHEDRAL EXPANDED STRUCTURAL FORMULA: SHOWING EACH BOND LINE. MOLECULAR FORMULA CH 4

ETHANE C 2 H 6 MOLECULAR FORMUL EXPANDED STRUCTURAL FOR CONDENSED STRUCTURAL FORMULA: WITH EACH CARBON ATO CH 3 – CH 3 ITS ATTACHED HYDROGEN ATOMS.

ALKANES CNH 2 N+2 N: NUMBER OF CARBON ATOMS

NAMING OF ALKANES PREFIX + ANE CNH 2 N+2

TASK WITH A PARTNER, NAME THE FOLLOWING COMPOUNDS: • C 2 H 6 • C 8 H 18 • CH 4 • C 5 H 12 • C 7 H 16 • C 10 H 22 4 MINUTES

LINE-ANGLE FORMULA PROPANE BUTANE CH 3 -CH 2 -CH 3 PENTANE CH 3 -CH 2 -CH 3

NAMING SUBSTITUENTS IN THE IUPAC SYSTEM: • REMOVING A H FROM AN ALKANE IS CALLED ALKYL GROUP. -ANE -YL • HALOGEN ATOMS ARE NAMED AS HALO. -INE -O -OH -NO 2 HYDROXYL NITRO

STEP 2 NUMBER THE CARBON ATOMS STARTING FROM THE END NEAREST A SUBSTITUENT. STEP 3 GIVE THE LOCATION AND NAME OF EACH SUBSTITUENT (ALPHABETICAL ORDER) AS A PREFIX TO THE NAME OF THE MAIN CHAIN.

GIVE THE NAME OF: CH 3─CH─CH 2─CH 3 STEP 1 LONGEST CHAIN IS BUTANE. STEP 2 NUMBER CHAIN. CH 3─CH─CH 2─CH 3 1 2 3 4 STEP 3 LOCATE SUBSTITUENTS AND NAME. 2 -METHYLBUTANE

GIVE THE NAME OF: CH 3─CH─CH─CH 3 STEP 1 LONGEST CHAIN IS BUTANE. STEP 2 NUMBER CHAIN. CH 3─CH─CH─CH 3 1 2 3 4 STEP 3 LOCATE SUBSTITUENTS AND NAME. 2, 3 -DIMETHYLBUTANE

CL CH 3─CH 2─CH─CH─CH 3 STEP 1 LONGEST CHAIN IS PENTANE. STEP 2 NUMBER CHAIN FROM END NEAREST SUBSTITUENT. CL CH 3─CH 2─CH─CH─CH 3 5 4 3 2 1 STEP 3 LOCATE SUBSTITUENTS AND NAME ALPHABETICALLY.

CH 2 CH 3─CH─CH 2─CH 3 STEP 1 LONGEST CHAIN HAS 5 CARBON ATOMS (PENTANE). STEP 2 NUMBER CHAIN FROM END NEAREST 1 2 SUBSTITUENT. CH 2 CH 3 4 5 3 CH 3─CH─CH 2─CH 3 STEP 3 LOCATE SUBSTITUENT AND NAME.

CONSTITUTIONAL ISOMERS • HAVE THE SAME MOLECULAR FORMULA. • HAVE DIFFERENT ATOM ARRANGEMENTS (DIFFERENT STRUCTURAL FORMULA). CH 3 CH 2 CH 3 BUTANE C 4 H 10 2 -METHYLPROPANE C 4 H 10 CH 3 CHCH 3

CYCLIC HYDROCARBON - CYCLOALKANE = CYCLOBUTANE = CYCLOPENTANE = CYCLOHEXANE

PHYSICAL PROPERTIES OF ALKANES • • NONPOLAR INSOLUBLE IN WATER. LOWER DENSITY THAN WATER. LOW BOILING AND MELTING POINTS. • GASES WITH 1 -4 CARBON ATOMS. (METHANE, PROPANE, BUTANE) • LIQUIDS WITH 5 -17 CARBON ATOMS. (KEROSENE, DIESEL, AND JET FUELS) • SOLIDS WITH 18 OR MORE CARBON ATOMS.

BOILING & MELTING POINTS OF ALKANES NUMBER OF CARBON ATOMS ↑ NUMBER OF BRANCHES ↑ CH 3 CH 2 CH 3 BP & MP ↑ BP & MP ↓ CH 3 CHCH 3

CHEMICAL REACTIONS OF ALKANES LOW REACTIVITY 1 - COMBUSTION: • ALKANES REACT WITH OXYGEN. • CO 2, H 2 O, AND ENERGY ARE PRODUCED. • ALKANE + O 2 CH 4 + 2 O 2 CO 2 + H 2 O + HEAT CO 2 + 2 H 2 O + ENERGY

CHEMICAL REACTIONS OF ALKANES LOW REACTIVITY 2 - HALOGENATION: ALKANES REACT WITH HALOGENS. CH 4 + CL 2 CH 3 CL + HCL CHLOROMETHANE CH 2 CL 2 + HCL DICHLOROMETHANE CH 2 CL 2+ CL 2 CHCL 3 + HCL TRICHLOROMETHANE CHCL 3+ CL 2 CCL 4 + HCL TETRACHLOROMETHANE HEAT OR LIGHT CH 3 CL+ CL 2 HEAT OR LIGHT

SOURCES OF ALKANES • NATURAL GAS – 90 TO 95 PERCENT METHANE. – 5 TO 10 PERCENT ETHANE, AND – A MIXTURE OF OTHER LOW-BOILING ALKANES, CHIEFLY PROPANE, BUTANE, AND 2 -METHYLPROPANE. • PETROLEUM – A THICK LIQUID MIXTURE OF THOUSANDS OF COMPOUNDS, MOST OF THEM HYDROCARBONS, FORMED FROM THE DECOMPOSITION OF MARINE PLANTS AND ANIMALS. (C 1 -C 4) (C 5 -C 10) (C 10 -C 18) (C 15 -C 25) ( C 25)

ORGANIC CHEMISTRY 1. 1 ALKANES LEARNING OBJECTIVES: TO UNDERSTAND THE STRUCTURE AND NOMENCLATURE OF ALKANES. KEY WORDS: • • ORGANIC COMPOUNDS HYDROCARBON SATURATED HYDROCARBON ALKANE

EXIT QUESTIONS • WHAT IS THE FORMULA FOR ALKANE? • WHAT IS THE CONDENSED STRUCTURAL FORMULA FOR PROPANE? • GIVE THE NAME OF: CH 3─CH─CH 2─CH 3