ALKANES

Preparation of alkanes can be divide into 4 which are hydrogenation of alkanes, reduction of alkyl halide, wurtz reaction and hydrolysis of grignard reagent. 

Hydrogenation of alkanes is addition of hydrogen (H) to an alkenes for forming an alkanes with platinum(Pt), palladium (Pd) and nickel (Ni) as a catalyst.

Reduction of alkyl halide is addition of Zink (Zn) to the alkyl halide to form an alkanes with HX as the catalyst. "X" represent halogen group such as (Cl, Br, I).

Wurtz reaction is addition of Sodium atom (Na) to the alkyl halide with ether as the catalyst to form an alkanes. 2Na been used in the example because i want to show the balance chemical equation.

Hydrolysis of grignard reagent involved two step which firstly form grignard reagent and the second is forming the alkanes. Forming grignard reagent is combination of alkyl with magnesium (Mg) and X which is halogen group. The second step is addition water (H2O) to the grignard reagent with hydrogen ions as catalyst to form an alkanes.

Reaction of an alkanes can be divided into three which halogenation, ring opening and combustion.

Halogenation have three step which initiation, propagation and termination. 
Initiation is breaking halogen to the free radical by addition of UV. 

Propagation have two step, the first one is alkane and free radical halogen will forming free radical alkane and halogen. Second, free radical alkane will react with halogen to form alkyl halide and free radical halogen. 

Termination have three step, first free radical halogen react with free radical halogen forming halogen. Second, free radical alkane react with free radical halogen forming alkyl halide. Third step, free radical alkane react with free radical carbon forming alkane.

Ring opening only occurs for cyclopropane. Cyclopropane can involved in substitution or addition process.

Combustion is process alkanes react with oxygen and forming carbon dioxide and water.

Baeyer strain theory explain about angle bond, angle strain and the reactivity. cyclopentane has the highest angle bond follow by cylobutane and cyclopropane. However, cyclopropane has the highest angle strain and be the most reactivity follow by cyclobutane and cyclopropane.

Introduction to organic chemistry

First thing first, we need to know on how to write the general formula. General formula can be divide into two which molecular formula or emprical formula. Molecular formula is the actual number of atoms represent in a molecule.For example, butene C₄H_8. While, emprical formula is the simplest ratio of atoms in a molecule. For example butene, instead of write as C4H8 we need to write as CH2.

structural formula can be divide into 3 which are expanded structure, condensed structure and skeletal structure. Expanded structure shows every atoms in a molecule. 

Condensed structure shows all atoms, but omits some or all of the verticle and horinzontal bonds. it makes it easier to write the formula in a line. 

The last structural formula is skeletal structure it shows just the carbon skeleton and the functional group. it does not need to shows carbon atoms and hydrogen atoms that attached directly to carbon atoms.

There are three structural isomers which chain, position and functional group. All of them have same chemical properties but different physical properties.

Chain can be represent as linear or branch. both of them has  similar number of atoms but different arrangement that make them be a different molecule. 

Next, position of the functional group that be added at the different side also make them be a different molecule. 

Last structural isomers is functional group, the different functional group added to the molecule will form different molecule even though total of each atoms are equally.

Stereoisomerism, include geometrical isomers and optical isomers. Geometrical isomers have cis- isomers and trans-isomers. the different between this two isomer just the arrangement of same functional group. cis-isomers will have same functional group in adjacent. while trans- isomers will have the same functional group in opposite site.

Optical isomers has two characteristic which are stereoisomer not superimposible  and not mirror image. Chiral carbon is a carbon that has four different functional group attaches to itself. From this optical isomers, we can know how many isomer presence by 2ⁿ , n is represent how many chiral carbon in a molecule.

Alkanes soluble in non polar solvent but insoluble in water. the boiling point of alkanes will increase as the number of carbon in a molecule increase. Besides, boiling point of alkanes  in the form of branch more higher compare to the linear arrangement. For number of carbon from 1 to 4 it in the form of gasses at normal temperature, while carbon 5-18 in the form of liquids, and number of carbon more than 18 in the form of solid.

That's all for this chapter, hope this will help you💕