Science - Chemistry - Organic Chemistry - C7 Flashcards
what is organic chemistry ?
the study of substances which contain carbon atoms
what is a hydrocarbon ?
A hydrocarbon is any molecule which contains hydrogen and carbon atoms only
give an example of a hydrocarbon
C10H22 - decane (an alkane)
what are alkanes ?
madeup of chains of 1 carbon for every 4 hydrogen
are there double carbon bonds in alkanes ?
no
how are carbon bonds saturated ?
all atoms from bonds with as many other atoms as they can
list first for alkanes
methane
ethane
propane
butane
what is the general formula for alkenes
CnH2n+2
give 3 properties of hydrocarbons :
- the shorter the molecule, the less viscous it is
- the shorter the molecule - the lower the boiling point is
- the shorter the molecule - the more flammable it is
how does combustion with hydrocarbons work ?
carbon and hydrogen react with oxygen to form carbon dioxide and water vapour, energy is also released
what is complete combustion in hydrocarbons ?
carbon atoms are fully oxidised
what is the equation for complete combustion ?
hydrocarbon + oxygen - carbon dioxide + water vapour
what is crude oil ?
a fossil fuel made up of a different of different compounds, formed of plants and animals, mainly plankton - which dies millions of years ago and were buried in mud. Over millions of years and high temperatures crude oil was formed
how do we get crude oil ?
drilling it up from underground
is crude oil renewable ?
no
what is crude oil made up of- be specific ?
hydrocarbons, mainly alkanes
how is fractional distillations used to split up different hydrocarbons in crude oil ?
- crude oil is pumped into a fractionating column
- crude oil evaporates
- crude oil is pumped into the bottom of the column
- the column is hottest at the bottom, cooler at the top
- gas rises up the column and gradually cools
- different compounds have different boiling points so they condense at different temperatures
- hydrocarbons that similar number of carbon atoms condense in similar levels
- the group of hydrocarbons that condense together are called fractions
give example of hydrocarbons which cool near the bottom of the column
- bitumen
- heavy fuel oil
give examples of hydrocarbons which cool near the middle
- kerosene
- ## diesel oil
give examples of hydrocarbons which cool near the top of the column
- LPG
- petrol
what is crude oil used for ?
fueling cars, planes, trains
what does LPG help do ?
is stored in high pressure in a bottle as a gas, when tap on bottle is open fuel vaporises and flows to burner where its ignited
what does petrol help to do ?
liquid, so is stored in fuel tanks and can flow to the engine where its mixed with air before ignited
how does viscous hydrocarbons help ?
they are gloopy, so help lubricate engine parts and cover roads
what is feedstock, and how are they used
petrochemical industry use hydrocarbons as feedstock, and make new compounds for things like polymers, solvents, lubricants and detergents
what are organic compounds ?
compounds containing carbon atoms
are all products from crude oil organic compounds ?
yes
what is a homologous series ?
groups of carbon atoms products which bond together
give examples of homologous series
alkanes
alkenes
alcohols
carboxylic acids
do compounds in the same homologous series share similar properties ?
yes
what is cracking ?
splitting long chain hydrocarbons into shorter ones
why do we use cracking ?
long chain hydrocarbons are less useful, as they are more gloopy form things like tar
what is good about short chain hydrocarbons ?
they are flammable, good for fuels
what else can be produced from cracking ?
substances like ethene, which is useful for plastics
how does cracking work ?
thermal decomposition
what is thermal decomposition ?
breaking molecules down by heating them