2. Hydrocarbons- alkanes, alkene, alkynes Flashcards
(20 cards)
what is the main source of hydrocarbons.
Crude oil
Hydrocarbons are
compounds containing carbon and hydrogen only
Hydrocarbons provide us with
fuels such as petrol, diesel and kerosene
Hydrocarbons are also the starting compounds we use to
make many new compounds, such as most of the plastics we meet in everyday life.
Crude oil is extracted from
porous seams of rock found beneath an impervious layer of rock within the Earth’s crust
General formula of alkanes
CnH2n+2
Alkanes are unreactive towards most chemical reagents because
there is only a very small electronegativity difference between carbon and hydrogen
Alkanes are essentially non-polar so there are
no areas of higher or lower electron density that can be attacked by reagents such as acids and alkalis
The majority of compounds found in the mixture of
hydrocarbons we call crude oil are
alkanes
the molecular formula of pentane
C5H12
the simplest class of hydrocarbons
only contain single bonds between carbon atoms
alkanes
saturated hydrocarbons are
hydrocarbons that contain only single bonds between carbon atoms.
They are called saturated because each carbon atom is bonded to as many hydrogen atoms as possible (bonded to four other atoms )
In other words, the carbon atoms are saturated with hydrogen
alkanes are called saturated because
each carbon atom is bonded to as many hydrogen atoms as possible (bonded to four other atoms )
In other words, the carbon atoms are saturated with hydrogen
saturated implies that
no carbon-carbon multiple bonds exist in these organic compounds
Crude oil is found where
trapped in layers of rock beneath the surface of the Earth.
Crude oil is a
complex mixture of hydrocarbons – alkanes, cycloalkanes and aromatic compounds
Cycloalkanes are
saturated hydrocarbons in which there is a ‘ring’ consisting of three or more carbon atoms.
a cycloalkane does not follow the general alkane formula, CnH2n + 2. because
the two end carbon atoms in an alkane chain bond to each other, forming a closed ring.
Therefore there are two fewer hydrogen atoms in a cycloalkane compared with its equivalent straight chain alkane
why are there fewer hydrogen atoms in a cycloalkane compared with its equivalent straight chain alkane
because the two end carbon atoms in an alkane chain bond to each other, forming a closed ring
Another class of hydrocarbons called aromatic hydrocarbons, which are also known as arenes, are based on
hexagonal benzene rings
