Organic Chemistry. Introduction to Organic Chemistry

Transcription

1 Organic Chemistry Introduction to Organic Chemistry

2 What is Organic Chemistry? Organic Chemistry is the study of carbon containing compounds Organic compound Is molecular compound of carbon Is made up of carbon and hydrogen exclusively (hydrocarbons) or carbon, hydrogen and small amount of other elements such as N,P,O,S and halogen atoms (hydrocarbon derivatives)

3 What is Inorganic Chemistry? Inorganic Chemistry is the study of the rest of the elements

4 Examples of Organic Compounds Sugar, fat, oil, protein, starch Clothing - wool, silk, cotton, nylon, spandex, acrylic fabrics Cosmetics creams, perfumes Medicine Plastic, rubber, paints Pesticides, herbicides

5 Compounds found in nature Produced through process called biosynthesis Sugar, cotton, wool Compounds made by man Synthetic compounds Nylon, rubber, creams

6 History of Organic Chemistry Historically, organic compounds were obtained naturally from living organisms (plants and animals) 1828 Fridrich Wohler synthesized first organic compound (urea) from inorganic reactants

7 We now have found ways of synthesizing these organic compounds (with the desirable properties of the natural compounds)

8 Synthesis of New Organic Compounds Synthesis from elemental carbon and hydrogen (other elements) is not always possible Majority of organic compounds is synthesized from other organic compounds (hydrocarbons)

9 Sources of hydrocarbons Wood Products that result from fermentation of plants Fossil fuels (origins in organic matter) Coal Petroleum (crude oil) Natural gas

10 Petroleum Main source of the hydrocarbons that are used for fuels and many other products (eg. Plastic and synthetic fabric) Mixture of solid, liquid and gaseous hydrocarbons Petroleum is process at oil refineries (fractional distillation)

11 Sooo.. Many organic compounds There are approximately 6 times as many organic compounds as there are inorganic compounds Why is this so?

12 Why is Carbon so Special? The unique characteristics of carbon allow for large number of organic compounds Carbon forms a total of four covalent bonds Thus it can bond to itself or many different atoms

13 Carbon atoms can bond together to form a variety of geometrical structures

14 Forms single, double or triple bonds

15 Representing Organic Compounds Organic compound Structural diagrams Complete structural diagram Molecular formula Structural models Ball-and-stick models Condensed structural diagram Space-filling models Line structural formula Dash-wedgeline structures Skeletal structure

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17 Molecular formula Shows the actual number of atoms of each element in a molecule Disadvantage : it does not provide information about structure Eg. Draw a skeletal structure of pentane, C 5 H 12.

18 Isomers Are compounds with the same molecular formula but different molecular structures Named differently Have different physical and chemical properties

19 Structural diagrams Also called structural formulas Are two dimensional representation of the arrangement of the atoms in molecules

20 Advantages: gives complete information about the arrangement of atoms in a molecule Disadvantages: does not provide information about the spatial orientation of atoms

21 Complete Structural Diagram Also called expanded structural diagram Shows all the atoms in a structure and how they are bonded to one another Bonds are shown with straight lines

22 Disadvantage?

23 A single line represents one pair of electrons (a single bond) = A double line represents two pairs of electrons (a double bond) A triple line represents three pairs of electrons (a triple bond)

24 Condensed Structural Diagram Shows the kind and number of atoms present Only shows bonds between carbon atoms The bond between hydrogen and carbon is assumed to be present

25 Expanded Molecular Formula Shows groupings of atoms without drawing lines to show the actual bonds that occur, they are assumed to be present Brackets are used to indicate the location of branched chains

26 Line Structural Diagram The end of each line, and the points where lines meet, represent carbon atoms Hydrogen atoms are assumed to be present in the correct number Gives you a sense of the threedimensional nature of the bonds

27 Representing Structures Complete Structural Diagram Condensed Structural Diagram Expanded Molecular Formula Line Structural Diagram CH 3 CH 2 CH 2 CH 3 CH 3 CH 2 CH 2 CH 2 CH 3

28 Common molecular shapes in organic chemistry

29 Classifying Hydrocarbons Chemists group hydrocarbons and other organic compounds into categories based on their properties The International Union of Pure and Applied Chemistry (IUPAC) developed a set of rules for naming the compounds in each category

30 Organic Compounds Hydrocarbons Hydrocarbon Derivatives Aliphatic Hydrocarbons Alicyclic Hydrocarbons Aromatic Hydrocarbons Saturated Hydrocarbons Unsaturated Hydrocarbons Alkanes Alkenes Alkynes

31 Terms To Know Saturated organic compounds in which each carbon atom is bonded to the maximum number of hydrogen atoms, thus containing only single bonds Unsaturated organic compounds in which the carbon atoms do not have the maximum number of hydrogen atoms and thus have double or triple bonds

32 Classifying Hydrocarbons Look at the following compounds. If you were to classify them, how would you do it?

33 Single Bond Compounds These are called Alkanes!

34 Double Bond Compounds These are called Alkenes!

35 Triple Bond Compounds These are called Alkynes!