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KIMIA DASAR I

KIMIA DASAR I. SENYAWA ORGANIK. Materi tanaman / hewan Makanan Bahan farmasi/ kosmetik Plastik Komponen minyak bumi Pakaian. Some organic chemicals. Medicines Active Pharmaceutical Ingredients Excipients. DNA. Fuels. Materials. Essential oils. Pigments. Carbon (C).

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KIMIA DASAR I

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  1. KIMIA DASAR I

  2. SENYAWA ORGANIK Materi tanaman / hewan Makanan Bahan farmasi/ kosmetik Plastik Komponen minyak bumi Pakaian

  3. Some organic chemicals • Medicines • Active Pharmaceutical Ingredients • Excipients DNA Fuels Materials Essential oils Pigments

  4. Carbon (C) UnsurkehidupandiatasbumiadalahCmengapa ??? memiliki 4 buahelektron bonding yang dapatmembentukikatankovalen yang kuat, dapatberupaikatantunggaldanrangkap (2 atau 3)

  5. Molekul organik paling sederhana: Susunan OKTET yang stabil metana Covalent Bonding – Atoms Share Electrons

  6. ALKANA

  7. Hibridisasi Bentuk dasar Bentuk tereksitasi 4 sp3

  8. Struktur tetrahedral pada metana Carbon yang menunjukkan hibridisasi sp3 4 buah ikatan C-H yang ekivalen (ikatan s) Semua ikatan tunggal dinamakan ikatan s

  9. Alkana CnH2n+2 consist of only carbon and hydrogen bonded by single covalent bonds single Skeletal structure of only carbon atoms

  10. Contoh : 2-metilbutana 3-etil-5-metilheksana 3 + 5 = 8  4-etil-2-metilheksana 4 + 2 = 6 

  11. SIFAT FISIK Senyawa non polar, densitas <1, dengan air membentuk dua lapisan Larut dalam pelarut organik non polar Alkana C  4, berbentuk gas, Alkana Mr >, berbentuk cair, Alkana Mr >>>, berbentuk padat Semakin besar jumlah atom C, Mr molekul semakin >, gaya dispersi tiap molekul >, titik didih semakin tinggi Alkana bercabang td < alkana rantai lurus padanannya Ada pengaruh gaya van der Waals antar molekul Ikatan tunggal mampu berotasi bebas

  12. Melting (blue) and boiling (pink) points of the first 14 n-alkanes in °C.

  13. Isomers – the have the same molecular formula, but a different structuresStructural Isomers – same molecular formula, but atoms are bonded in different orders. C4H10 – has two isomers, n-butane and isobutane (2-methylpropane) Has the same molecular formula as n-pentane, C5H12 (2-methylbutane) Has different Physical Properties : m.p, b.p. density (2,2-dimethylpropane)

  14. CYCLOALKANES CnH2n

  15. Cyclopropane Cyclobutane Cyclopentane

  16. metilsikloheksana tert-butilsiklopentana 1,2-dimetilsikloheksana

  17. How to draw Cyclohexane ? put in axial H’s put in equitorial H’s

  18. Reactions of Alkanes Combustion Dehydrogenation Halogenation – radical substitution reactions

  19. Halogenation Substitution Reaction– a reaction in which part of a small reacting molecule replaces an atom or a group of atoms on the organic molecule

  20. Alkyl Halides or Haloalkanes

  21. Naming them Tend to be Heavier than water More Toxic than Alkanes Tetrachloromethane or carbon tetrachloride 2-Chloro-3-methylbutane 3-Bromo-1-chlorobutane 1-Bromobutane 2-Chloropropane or Isopropyl chloride 1-Ethyl-2-fluorocyclohexane Trichlorofluoromethane (Freon-11) Dichlorodifluoromethane (Freon-12) 1,1,1, 2-Tetrafluoroethane Chlorofluorocarbons (CFCs) Refrigerant Gases, Ozone Depletion, More H’s more degradable

  22. d- d+ X is readily displaced by nucleophiles Nu - Electronegativity is defined as the ability of atoms to attract shared electrons in a covalennt bond ------------ leads to nucleophilic substitution in alkyl halides Symmetrical molecules have no dipole moment or have equal distribution of electrons within covalent bonds Therefore, they are unreactive!

  23. STEREOCHEMISTRY

  24. Isomers are different compounds that have the same molecular formula Structural isomers are isomers that differ because their atoms are connected in a different order CH3OCH3 ---- dimethyl ether and CH3CH2OH ---- ethanol Stereoisomers differ only in the arrangement of their atoms in space Geometric Isomers

  25. Enantiomers are stereoisomers whose molecules are nonsuperimposable mirror images of one another Involves a tetrahedral sp3 atom

  26. One structure can be superimposed on another If any of the groups attached to the tetrahedral atom are the same, the centre is achiral. The ultimate way to test for molecular chirality is to construct models of the molecule and its mirror image and then determine whether they are superimposable Screwdriver is achiral Socks are achiral Golf club is chiral Gloves are chiral

  27. Properties of Enantiomers Enantiomers have identical melting points and boiling points Enantiomers have identical solubilities in solvents Enantiomers have identical spectra and refractive index Enantiomers interact, and react with achiral molecules in the same manner Enantiomers interact and react with other chiral molecules at different rates Enantiomers rotate plane-polarised light by equal amounts but in opposite directions Chiral molecules are optically active Polarimeter is a devise used to measure the effect of plane-polarised light on an optically active compound

  28. No Correlation between the direction of rotation of plane polarised light and the absolute configuration of a molecule Clockwise Rotation (+) – dextrorotatory Anti-Clockwise Rotation (-) – levorotatory An equimolar mixture of two enantiomers is called a Racemic Mixture It is Optically Inactive

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