ALKANES Flashcards
What is an alkane
a fully saturated hydrocarbon
What shape are alkanes
tetrahedral around each carbon
bonding angles are 109.5
Why are alkanes used as fuels
they release large amounts of energy and burn quite readily
alkanes burn in plentiful oxygen completely*
What are alkanes used for in real life
used to power vehicles and to generate electricity by combustion
How to work out formula of a hydrocarbon being burnt
use the information given to write a volume ratio and deduce from there by balancing the equation
what is produced from incomplete combustion of alkanes
Carbon monoxide or Carbon(soot)
What happens in the initiation step of a free radical chain reaction
Radicals are produced using visible or UV light by homolytic fission
What happens in the propagation step of a free radical chain reaction
A radical can react with a non radical molecule, this creates a new radical which can react with other non radicals, this is called a chain reaction
What happens in the termination step of a free radical chain reaction
2 radicals react to form a non radical, this ends the chain reaction
Give the free radical substitution mechanism to make chloromethane
I Cl2 –>(UV) Cl. + Cl.
P Cl. + CH4 –> CH3. + HCl
CH3. + Cl2 –> CH3Cl + Cl.
T CH3. + Cl. –> CH3Cl
How can impurities be made in free radical reactions and how can this be reduced
An excess of radicals can react with the desired product to undergo further reactions, and the product of this can react even further
can be prevented by adding excess of the non radical molecule of the reaction
How can isomers be formed in free radical substitutions
as the radical will react anywhere on the hydrocarbon chain
