![]() Line formulas help show the structure and order of the atoms in a compound. They are assumed to be present to complete the octet of non-carbon atoms. Atom labels for all other elements are shown. Hydrogens that are attached to elements other than carbon are shown. Hydrogen atoms are omitted but are assumed to be present to complete each of carbon's four bonds. A carbon atom is present wherever a line intersects another line. Notice how COOH means C(=O)-O-H instead of CH 3-C-O-O-H because carbon does not have a complete octet and oxygens.īecause organic compounds can be complex at times, line-angle formulas are used to write carbon and hydrogen atoms more efficiently by replacing the letter "C" with lines. In example C, the carbon is double bonded to oxygen and single bonded to another oxygen. As you read through a a condensed formula, if you reach an atom that doesn't have a complete octet by the time you reach the next hydrogen, then it's possible that there are double or triple bonds. Also, notice the -OCH 3 is in written in parentheses which tell you that it not part of the main chain of carbons. The hydrogen's are important, but are usually there to complete octets. As you go through a condensed formula, you want to focus on the carbons and other elements that aren't hydrogen. Look at the examples below and match them with their identical molecule under the Kekulé structures and the line formulas. Condensed formulas can be read from either direction and H 3C is the same as CH 3, although the latter is more common. An example is CH 4, which represents four hydrogens attached to the same carbon. Also, if more than one of the same substituent is attached to a given atom, it is show with a subscript number. When this happens, parenthesis are used around the group of atoms to show they are together. Condensed structural formulas are also helpful when showing that a group of atoms is connected to a single atom in a compound. The order of the atoms suggests the connectivity in the molecule. Condensed structural formulas show the order of atoms like a structural formula but are written in a single line to save space and make it more convenient and faster to write out. Non-bonding valence shell electrons are omitted in these formulas.Ī condensed formula is made up of the elemental symbols. Each straight line segment represents a bond, the ends and intersections of the lines are carbon atoms, and the correct number of hydrogens is calculated from the tetravalency of carbon. Line formulas omit the symbols for carbon and hydrogen entirely (unless the hydrogen is bonded to an atom other than carbon). In condensed structural formulas, the bonds to each carbon are omitted, but each distinct structural unit (group) is written with subscript numbers designating multiple substituents, including the hydrogens. Kekule formulas is just organic chemistry's term for Lewis structures you have previously encountered. Simplification of structural formulas may be achieved without any loss of the information they convey. Many kinds of model kits are available to students and professional chemists, and the beginning student is encouraged to obtain one. Developing the ability to convert between different types of formulas requires practice, and in most cases the aid of molecular models. It will be more helpful if you become comfortable going from one style of drawing to another, and look at drawings and understanding what they represent. During this course, you will view molecules written in all three forms. The three different ways to draw organic molecules include Keku lé Formulas, Condensed Formul as, and Skeletal structures (also called line-bond structures or line formulas). Because organic chemistry can involve large molecules it would be beneficial if Lewis structures could be abbreviated. Through general chemistry, you may have already experienced looking at molecular structures using Lewis structures. When drawing the structure of a neutral organic compound, you will find it helpful to remember that N(Monomer) Polymer A + A + A + A + A …. AAAAA Reactants Products Synthesis Decomposition Single Replacement Double Replacement Polymerization Condensation Polymerizationħ Synthesis Reaction Example: making water 2 H2 + O2 2 H2OĮxample – bubbling soda H2CO3 H2O + CO2ġ3 Double Replacement Example – Mixing up ionic compounds NaCl + AgNO3 NaNO3 + AgClġ4 Acid-Base Reaction A + H+ AH+ AH A- + H+ 3 bonus points if you get it 100% correct! Draw the Lewis structure for this molecule. ![]() 3 bonus points if you get it 100% correct!"- Presentation transcript:ġ ET Below is a molecule of caffeine. Presentation on theme: "ET Below is a molecule of caffeine.
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