alkanes/ alkenes Flashcards
alkanes
saturated hydrocarbons
saturated
contains single C-C bonds only
naming alkanes
all end in ane
start depends on no. C
1 - Meth…
2 - Eth…
3 - Prop…
4 - But…
5 - Pent…
homologous series
- have similar chemical properties
- have same functional group
- have same general formula
- differ from next member by a CH2 unit
- shows gradual trend in physical properties
functional group
a group of atoms responsible for the chemical properties of a compound
eg functional group of alkanes is a single C-C (saturated bond)
molecular formula
shows exact no. atoms of each element present in a molecule
displayed formula
shows how atoms are arranged using lines to represent covalent bonds between atoms
structural formula
shows how atoms are arranged - without using lines to represent covalent bonds between atoms
general formuka
shows the simplest algebraic formula of a member of a homologous series
general formula of alkanes
CnH2n+2
why alkanes get thicker as length of carbon chain increases
larger so stronger intermolecular forces, more energy needed to overcome forces so alkanes are thicker as chain lengths increases
alkenes
unsaturated hydrocarbons
unsaturated
contains a double C=C bond
why no methene
can’t have a double bone with only one carbon
functional group of alkenes
double C=C bond
alkenes come from
cracking long chain alkanes
general alkene formula
CnH2n
alkenes displayed formula
can have the double bond between any of the carbons leading to alternate forms of each alkene
why do mtp/bp increase alkenes
more carbons so bigger molecules
intermolecular forces stronger
more energy to overcome
small molecule alkanes uses
FUELS
- combust easily
alkene uses
polymers
plastics
