IGCSE🤍

alkanes

saturated hydrogen means they contain and hydrogen atoms joined by single covalent bonds

What are the different types of alkanes?

• straight chains

• branched

• cyclic

What are the functional group of alkanes?

C-C

What is the general formula of alkanes?

C_nH_2n+2

What ‘s the reaction of alkanes?

• complete combustion: small alkane molecules are particularly useful as fuels because they combust readily releasing large amounts of energy (alkane + oxygen → carbon dioxide + water)

• incomplete combustion: this occurs when there is insufficient oxygen for complete combustion. this produces carbon particulates and carbon monoxide instead of, or as well as, CO2 (alkane + limited oxygen + carbon monoxide + carbon dioxide + water)

• chlorination: alkanes react with chlorine, Cl2, in the presence of UV light to produce chloroalkanes and a mixture of other products, in a free-radical substitution reaction

What are the properties of alkanes and alkenes?

• Alkanes are often used as fuels

• Alkanes are mainly obtained through the fractional distillation of pentroeulm

• Large alkane molecules can undergo catalytic cracking or thermal cracking to produce more useful, smaller alkane molecules

• When hydrocarbon fuels are burnt in car angles, they produce nitrogen oxdies (NOx), carbon monoxide (CO), carbon particles les and unbumed hydrocarbons. These must be removed from exhaust fumes by catalytic converters

• The combusion of hydrogen fuels containing sulfar releases the harmful pollutant sulfar dioxide (SO2), which causes acid rain

hydrocarbon

a compound that contains hydrogen and carbon

What is the study of organic chemistry?

the branch of chemistry that studies the compounds of carbon

homologous series

a sequence of compounds with same functional group and similar chemical properties in which the members differ by CH2

functional group

a substituent in a molecule that causes the molecule’s characteristics chemical reaction

What are the different types of formulae in organic chemistry?

Molecular Formula: shows the number of each type of atom present

• tells you nothing about the bonding within the compound

  • example:

    C4H8O2

Empirical Formula: gives the simplest possible whole number ratio of the different types of atom within a compound

• example:

  C4H8O

Condensed Formula: each atom is listed separately with atoms attached to its following

• an expectation of cyclic parts of molecules, where the carbons are grouped

  • example: (benzene)

    CH3CH2CH2COOH

what is a displayed formula?

shows all the atoms and all the bonds present (the bonds repereseted as lines)