Section 6 Flashcards
alkane with 1 carbon is called
methane
alkane with 2 carbons are called
ethane
alkane with 3 carbons are called
propane
alkane with 4 carbons are called
butane
alkane with 5 carbons are called
pentane
alkanes with 6 carbons are called
hexane
with what suffix do alkanes end?
-ane
what is the general formula of alkanes?
CnH2n+2
what are characteristics of alkanes?
- same chemical properties
- trend in physical properties
- same general formula
- same functional group
- single bonds
what is the suffix when naming side chains (alkyl groups)
-ane is replaced with -yl
e.g. methyl, ethyl
how do we number the C atoms of the main chain?
- start from the end from which a side chain first appears
- the position number is as LOW as possible
- if there are several possibilities: the alkyl group with alphabetic precedence receives the lower number
draw the structure of 2,4-dimethyl hexane
how do we name alkanes?
position number - side chain - main chain
generla formula of alkyl groups
CnH2n+1
general formula of alkenes
CnH2n
what is a hydrocarbon?
a compound of hydrogen and carbon only
what does an incomplete combustion produce?
carbon monoxide
soot (carbon particles)
water
when does an incomplete combustion reaction take place?
when there is not enough oxygen around
refinery gas
- used for cooking and heating
- raw material for industrial purposes
gasoline
mostly a fuel for motors (cars, boats)
kerosene
- fuel for aircrafts or heating
- solvent in paints
diesel
- a fuel for large vehicles (cars, buses, train)
- fuel to generate electricity and heat
fuel oil
- used as a fuel for ships and industrial heating
definition of fuel
a fuel is a substance which releases heat energy when burned
why is CO (carbon monoxide) a toxic gas?
It binds with haemoglobin in the red blood cells and prevents oxygen from being transported
describe the composition of crude oil on a chemical level
a mixture of different hydrocarbons with a very different chain length and structure
describe and explain the trend in the boiling and melting points of the alkanes
the higher the number of C-atoms (the longer the hydrocarbon chain) the higher the boiling point of the alkanes
-> the longer the carbon chain the stronger the intermolecular forces
-> the more energy needed to overcome these
crude oil
a mixture of hydrocarbons - molecules made of only carbon and hydrogen
how are the different compounds in crude oil separated?
by fractional distillation
fractional distillation for crude oils
1) the oil is heated until most of it has turned into gas, which enter a fractionating column
2) as the substances that make up crude oil reach a part of the column where the temperature is lower than their boiling points, they condense
3) bubble caps stop the separated liquids from running back down the column and remixing
what will each fraction contain?
- each fraction contains a mixture of hydrocarbons with similar boiling points
- they might contain saturated or unsaturated hydrocarbons
the longer the hydrocarbons have…
- higher boiling points
- they condense and drain out of the column early on
the shorter hydrocarbons have…
- lower boiling points
- they condense and drain out much later on, near the top of the column where it’s cooler
boiling point of Petrol / gasoline
70 degrees Celsius
boiling point of Kerosene
180 degrees Celsius
boiling point of Diesel
260 degrees Celsius
the longer the hydrocarbon chain…
- more viscous
- less volatile
- less flammable
- darker the hydrocarbon
why do bigger hydrocarbons evaporate more slowly at room temperature?
bigger molecules are more strongly attracted to their neighbours
volatile
describes how easily a substance vaporises
viscous
the resistance of particles in a fluid to flow or move
what is an example of a viscous liquid?
honey
give an example of a volatile liquid
gasoline
bitumen
surface for roads
name 4 fractions in the fractional distillation of crude oil
gasoline (petrol)
kerosene
diesel
bitumen
how is crude oil formed?
- formed naturally
- from remains of dead plants and animals in the sea which fell to the bottom
- layers of sediment formed on top of them
what type of resource is crude oil?
a finite, non-renewable resource
what is meant by the term homologous series?
a group of compounds that can all be represented by the same general formula
methane will react with bromine in the presence of UV light. what type of reaction is this?
substitution reaction
methane + bromine together with UV light will produce…
bromomethane + hydrogen bromine
draw the displayed formula; methane + bromine = bromomethane + hydrogen bromine
what type of reaction takes place when bromine water is added to an alkene?
an addition reaction
what do you expect to observe when an alkene is added to bromine water?
the solution would turn from orange-brown to a colourless solution
polymerisation
is the joining up of lots of little molecules (monomers) to make one big molecule (polymer)
what does LD-PE stand for? give one example
low density polyethene (plastic bag)
HD-PE
high density polyethene (plastic container, bottles)
what are the main uses of poly-propene?
bottle caps, boxes and storage containers
write the general reaction equation for the polymerisation of propene using the displayed formula
what is polychloroethene?
one of the hydrogen atoms in ethene is replaced by a chlorine
polymerising chloroethene gives you what?
polychloroethene
what’s the formula of polychloroethene?
CH2=CHCl
what is tetrafluoroethene?
a molecule derived from ethene in which all four hydrogen atoms are replaced by fluorine
write the general reaction equation for the polymerisation of terafluoroethene using the displayed formula
what is the main use of poly-tetrafluoroethene?
brand name: Teflon
- non-sticking pans
- GoreTex in clothing
functional group of alcohols
functional group of alkenes
functional group of esters
functional group of carboxylic acids
what are the molecules that react to form an ester?
carboxylic acid + alcohol
draw the structure of 3-ethyl-2methyl pentane
2,2-dimethyl butane
2-methyl pentane
draw the repeat unit of the monomer
state four characteristics of the members of a homologous series
- same general formula
- similar chem properties
- trend in phys properties
- same functional group
If you shake an unknown organic compound with bromine water and the orange bromine water is decolourised, the compound contains what?
a carbon-carbon double bond
Note the reaction equation of the addition of Br2 to propene with displayed and molecular formulae
