9. Hydrocarbons

Question 1

Homologous series

Answer 1

is series of compounds with same general formula, but varying by length of carbon chain and functional group

Question 2

Functional group

Answer 2

specific groups of atoms or bonds within molecule that are responsible for the characteristic chemical reactions of those molecules. The molecules have same functional groups undergo same or similar chemical reactions regardless the size of the molecule. These functional groups are bonded to the molecule by covalent bond.

Question 3

Isomerism

Answer 3

there molecules that have different structural formula but same molecular formula. There are Cis and Trans that is form of stereoisomerism in general such isomerism contain double bonds which cannot rotate.

Question 4

State the nomenclature of hydrocarbons (3 carbons -> prop-)

Answer 4

A rational nomenclature system should do at least two things. First, it should indicate how the carbon atoms of a given compound are bonded together in a characteristic lattice of chains and rings. Second, it should identify and locate any functional groups present in the compound. Since hydrogen is such a common component of organic compounds, its amount and locations can be assumed from the tetravalency of carbon, and need not be specified in most cases.

Propane, Propene, Propanol, propanamine, propanal, propanone, Propanoic acid, Propan amide, Methyl, propanoate, Propane nitrile

Question 5

What are the chemical characteristics of aliphatic hydrocarbons?

Answer 5

Are alkanes and alkenes that do not contain benzene ring

Question 6

What are the burning characteristics of aliphatic hydrocarbons?

Answer 6

Alkanes can react with O2 by combustion. reaction. It can burn with the presence of excess oxygen to produce CO2 and H2O. Also burn with a supply of O2 producing CO and H2O. And with extremely limited O2 producing C and H2O

Question 7

What are the substitution characteristics of aliphatic hydrocarbons?

Answer 7

Alkanes undergo substitution reaction with halogens. Substitution reaction undergo first initiation where the halogens react to form two radicals with UV light. Then it undergo propagation where both compounds use and produce free radicals and allot the reaction to continue. Last step is termination where the reaction remove the free radicals from the mixture and causes the compounds to react and pair up their electrons.

Question 8

What are the addition characteristics of aliphatic hydrocarbons?

Answer 8

Alkenes undergo addition reaction with hydrogen, to form alkanes with Ni catalyst and heat. With halogens, forming di halogenoalkanes. With hydrogen halides, forming halogenoalkanes. With water, forming alcohol with H2SO4 catalyst and heat.

Question 9

What are the elimination characteristics of aliphatic hydrocarbons?

Answer 9

It involves the removal of a small molecules from larger molecules. Halgenoalkanes with NaOH(alcoholic solvent) produces alkene. There is E2 mechanism, this reaction has one step, and it is biomolecular. The E1 mechanism involves the loss of halide first in the slow step and then followed by the loss of proton and formation of double bond in the fast step. This reaction is unimolecular

Question 10

What are the polymerization characteristics of aliphatic hydrocarbons?

Answer 10

Alkenes undergo addition reaction by breaking their double bonds and can be joined together to produce long chains known as polymers. Alkenes used in the reaction are called monomer.

Question 11

Chemical characteristics of aromatic hydrocarbons - Burning

Answer 11

This process is called combustion. Benzene is burned with O2 it produces CO2 and H2O. Usually benzene forms stinking fumes.
 2 C6H6(l) + 15 O2(g) ---> 
12 CO2(g) + 6 H2O(g) . The combustion process of benzene is hardly could be completed.

Question 12

Chemical characteristics of aromatic hydrocarbons - reactions with halogenes

Answer 12

Halogenation is type of electrophilic aromatic substitution. Chlorination and bromination of benzene are the same. Ferric bromide or ferric chloride are used (FeBr3, FeCl3), FeBr3 react with bromine Br2 to form Br2+–FeBr3-. This reaction help the benzene ring to react with Br and replaced by one H, consuming +FeBr4-, and produces benzene ring with Br, and HB+.

Question 13

Chemical characteristics of aromatic hydrocarbons - nitration

Answer 13

Nitration is type of electrophilic aromatic substitution. A mixture of concentrated nitric acid and sulfuric acids that acts as catalyst is used. This mixture produces water and nitronium ion NO2+, which is active in aromatic nitration. This can be used in the nitration of benzene, where NO2+ attacks on the ring and replaced by one H, that is reacted then with water

Question 14

Characteristics of aromatic hydrocarbons?

Answer 14

They contain a benzene ring