Hydrocarbons - 16

A family of organic compounds with the same general formula and same functional group, hence have similar chemical properties and undergo similar chemical reactions

Meth- , Eth- & Prop-

NIL & $C_nH_{2n + 2} \space$ where n greater than or equal to 1

-ane

Low melting & boiling point, insoluble in water, soluble in organic solvents

Combustion can be complete (burning in excess oxygen) or incomplete (burning in insufficient amount of oxygen), Alkanes react with halogens in the prescence of UV light

Complete: Alkane/alkene + oxygen —> Carbon dioxide + water, Incomplete: Alkane/alkene + oxygen —> Carbon monoxide + water

$CH_4 + Cl_2 \rightarrow CH_3Cl + HCl$

It decreases down the series; as percentage of carbon increases, tendency to go into incomplete combustion is higher and flame produced is smokier

It increases down the series; as the size and mass of the molecules increase down the series, the intermolecular forces of attraction between the molecules increases, resulting in members showing a gradation in physical properties

Carbon - Carbon double bond & $C_nH_{2n}$ where n is greater than or equal 2

-ene

Alkenes are obtained by catalytic cracking of petroleum (crude oil) and is the breaking down of long-chain hydrocarbons into smaller molecules

About 600°C, aluminium oxide or silicon dioxide catalyst

choose any valid alkene ($C_nH_{2n}$) first, then subtract its carbon and hydrogen counts from your starting alkane. The leftover atoms will form your remaining product (an alkane, another alkene, or $H_2$), ensuring both sides balance perfectly.

$C_{18}H_{38} \rightarrow 6C_2H_4 + C_6H_{14} \space and \space C_{18}H_{38} \rightarrow C_8H_{16} + C_{10}H_{20} + H_2$

Produce short-chain alkenes, produce hydrogen gas for manufacture of ammonia, produce petrol due to greater demand

Some fats and oils are polyunsaturated and the higher the percentage of carbon-carbon double covalent bonds, the lower the melting point. Fats are solids at room temp while oils are liquid

Combustion where alkenes have higher % of carbon than alkanes, burning with sootier flames, and addition reactions where an unsaturated organic compound combines with another molecule to form a single compound

Moderately high temp, nickel catalyst

$Alkene + H_2 \rightarrow Alkane $

Converting vegetable oil (polyunsaturated fat) to margarine

Nothing specific other than room conditions

$Alkene + Br_2 \rightarrow bromoalkane$

Test for unsaturation. alkene: reddish brown decolourises, alkane: reddish brown remains