organic chemistry Flashcards
what is the definition of hydrocarbon
hydrocarbon are organic compounds that contain hydrogen and carbon
what are the sources of fossil fuels
1.decayed plants & animals
2. organic compounds such as fossil duels and carbon
3. fossil fuels are burnt in presence of oxygen = combustion
what are the types of fossil fuels
- crude oil
- natural gases
- coal
where is crude oil found
crude oil is found in sea beds or underground on land
where are natural gases found
methane found in crude oil
where is coal found
mainly carbon
define petroleum (crude oil)
petroleum is aliquid mixture of hydrocarbons
what method is used to separate crude oil/ petroleum
fractional distillation
what us the abbreviation for crude oil
pretty people never kiss dirty looking boys
what are the substances obtained from crude oil
petroleum
petrol
naphtha
kerosene
diesel oil
lubricating oil
bitumen
are fractions pure substances
fractions are a mixture of substances that re not pure as they have varying boiling point
state the relation btw length and size of hydrocarbons and boiling point
the longer the hydrocarbon, the bigger the hydrocarbon the higher the boiling point
why is fractional distillation important for crude oils
as different fractions have different purposes
what are biofuels
biofuels are renewable energy sources that come from animals and plants
what is the process to obtain biofuels
biofuels burn = CO2 produce = absorbed by photosynthesises by sugar canes = no excess CO2 produced
how are biofuels obtained
by fermenting sugar in sugarcane plants
what is the definition of homologues series
a group of organic compounds with the same general formula, same functional group having similar chemical properties and consecutive member differing from each other by a -CH2- unit
what are the characteristics of crude oil
- general formula
- differs by -CH2- unit
- same functional group = same properties
- similar reactions
5.gradual change in physical properties as molecular size inc
what are the physical properties of homologues series
melting and boiling point
flammability
viscosity
density
solubility in organic solvent
name the 1st 3 alkanes, name and no. of atoms
1, methane
2. ethane
3, propane
what is a functional group
specific atoms bonded in certain arrangement that give a compound certain physical and chemical property
what is the definition of alkanes
alkanes are saturated hydrocarbons which have a c-c single bond
what is the general formula of alkanes
CnH2+2
what is the source of alkanes
crude oils
what is the structure of alkanes
simple covalent molecular structure
what is the physical properties of alkanes
low melting and boiling point due to simple covalent molecular structure with weak forces of attraction
solubility in organic solution
what are the chemical reactions of alkanes
- combustion
- substitution
- cracking
how does complete combustion work with alkanes
alkanes are burnt in the presence of excess oxygen to produce CO2 and H2O = complete combustion
how does incomplete combustion work with alkanes
alkanes burn in the presence of limited oxygen to produce CO and H2O
how does substitution work with alkanes
substitution is the reaction of saturated compounds & catalysed under the presence of uv light
what is the definition of substitution
substitution is the process of an atom replaced by another atom or group of atoms
what is the reaction given substitution
methan + cl =
what is the definition of cracking
cracking is process where larger hydrocarbon molecules are broken down into smaller hydrocarbon molecules
what are the conditions needed for cracking
- solid catalyst
- high temperature
state the 2 general equations in cracking
large alkane = small alkene + small alkane
large alkane = small alkene + H2
what is the importance of cracking
during fraction distillation of crude oil, large amount of the nigger alkanes molecules is obtained . cracking is important to the higher demands of fractions containing smaller molecules
what does cracking provide
high quality gasoline
important raw materials - ethane and propane
source of hydrogen to make ammonia to make fertilizers
what are the uses of alkanes
use as fuels
methane = main natural gas
alkanes = alkenes by cracking
