Sticky Note!

Due to loads of distractions ( which includes my laziness ), I haven’t been able to keep up with updating this blog in the last few months. This note is just to say that I won’t be able to continue blogging here for at least a few months more. After that, all that gets updated here would be more of my personal notes or kind from whatever I study, which will not be limited to Maths and Physics, and which will completely exclude Chemistry. Though I might post some topics from it randomly as it is something I really love to study.

Anyway, thanks for all your comments! When I’d started this blog initially, I only thought of it as a place to gather my notes. Never really thought that it might actually help someone out. (-: Glad to know that!

So then, till next time!~

Nomenclature of Organic Compounds

Rules ( according to IUPAC ) :

1. Count the total number of carbon atoms.

2. Number them from an end. If other groups are present, number them according to the following priority ( decreasing ) list :

-COOH , -COCl , ( R – alkyl group ) , -CONH₂ , -CN , -HC=O , >C=O , -OH , -NH₂ , >C=C< , -C=C-

R , C₆H₅- , OR , Cl , Br , NO₂ etc. are prefix substituents.

3. If more than one functional group are present, they are numbered by adding di, tri etc before the class suffix.

4. All the names should have the names of individual groups arranged in alphabetical order.

5. In the name, two vowels ( one at the end of one group and other at start of another ) should never come together. The last letter of the prefix group should be changed to a consonantand only if this is not possible should the first letter of the suffix group be changed.

6. The carbon number to which any group is attached should be written right before it, and not at the beginning of the name.

7. In case of branched chains, they are named as alkyl groups, separately as a chain, and their names are enclosed in brackets.

8. The substituents are given the lowest numbers possible, so that in the final name, the total of numbers is the lowest possible for the compound. But, of course, the priority list is followed.

9. Numerical prefixes ‘ bis ‘, ‘ tris ‘ etc., are used to indicate multiplicity of substituted substituent.

 

 

Functional Groups : ( all of the above rules have to applied )

1. Alkane : -ane [ methane, propane, heptane ]

Trivial naming :

               

              

2. Alkene : -ene [methene, propene, heptene ]

3. Alkyne : -yne [methyne, propyne, heptyne ]

4. Alcohol : -ol , hydroxy-

Acc. to new rules, if more than two alcohol groups are attached in succession to a chain of carbon atoms, the naming is done as, for example, propane – 1, 2 , 3 – carbol.

CH₂ – CH – CH₂

  |         |        |

OH    OH     OH

5. Aldehyde : -al , oxo- , formyl-

Acc. to new rules, if more than two aldehyde groups are attached in succession to a chain of carbon atoms, the naming is done as, for example, propane – 1, 2 , 3 – carbaldehyde.

CH₂ – CH – CH₂

  |         |        |

CHO  CHO  CHO

6. Ketone : -one , oxo-

7. Ether : alkoxy alkane ( R-O-R’ )

Aliphatic – R = chain having less carbon atoms

Aromatic – R = the aliphatic chain attached to a benzene ring

Aromatic – If another aromatic group is present instead of an aliphatic chain, the compound is named using di, tri etc.

8. Nitrile : -nitrile* ( the last letter ‘e’ of the primary suffix is not removed ) , cyano-

9. Isocyanide : alkyl isocyanide , alkyl isonitrile , alkyl carbylamine

10. Amine : -amine , amino-

11. Acid : -oic acid

12. Ester : alkyl alkanoate – alkyl = alocohol part , alkanoate = acid part

13. Halide : halo-

14. Amide : -amide , carbamoyl-

15. Nitro : nitro-

16. Acid Halide : -oyl halide

17. Aromatic Compounds : These are more commonly known by their trivial names. They follow all the above listed rules as such. A special rule of aromatics is the definitions of ortho, meta and para substitutions, and naming based on it.

18. Cyclo Compounds : These are named exactly as the aliphatic compounds, just with a ‘ cyclo ’ added before the primary ring suffix. Another important rule is that if a side chain attached to the ring contains a multiple bond or a functional group, the alicylic ring is treated as substituent irrespective of the size of the ring.

              

 

Basic Concepts of Organic Chemistry

General Organic Chemistry

Basic Concepts

1. Property of catenation – leads to a variety of covalent compounds.

2. First organic compound prepared in lab – by Wohler – Urea from ammonium cyanate.

NH₄CNO –> NH₂CONH₂

3. First organic compound synthesised from its elements – by Kolbe – Acetic acid.

4. Hybridisation : sp³ , sp² , sp – influences the bond length, bond enthalpy and electronegativity of org compounds.

Bond length – sp³ > sp² > sp

Bond enthalpy – sp³ < sp² < sp

Electronegativity ( depends on % of s character ) – sp³ < sp² < sp

 

5. Structural Representations : Lewis structures, complete, condensed and bond-line structural formulae.

Complete Structural Formula :

Condensed Structural Formula :

CH₃CH₃ , CH₃OH , H₂C=CH₂

Bond-line Structural Formula :

 

6. 3D Representation on paper : Solid and dashed wedges are used to represent a 3D structure. Normally known as wedge-and-dash structure, wedges are used to indicate atom/molecule jutting out of paper, and dashes for atom/molecule going in.

7. Projection Formulae : Molecules are observed in a ray of light, and using some conventions, are presented in a 2D form on paper. Different projection formulae include – Fischer projection, Newman projection, and Sawhorse projection formulae.

Parabola

Conic Sections

A conic section is the locus of a point which moves so that its distance from a fixed point ( focus ) is in a constant ratio ( eccentricity ) with a fixed straight line ( directrix ).

Eccentricities :

e = 1 - Parabola

e < 1 - Ellipse

e > 1 - Hyperbola

e = sqrt. 2 - Rectangular Hyperbola