Organic Chemistry Flashcards
what are hydrocarbons?
any compound formed from only hydrogen and carbon atoms
what are alkanes?
the simplest type of hydrocarbon
what is the general formula for alkanes?
CnH2n+2
what is a homologous series?
a group of organic compounds that react in a similar way
what are saturated compounds?
each carbon atom forms four singular covalent bonds
what are the first 4 alkanes?
methane, ethane, propane and butane
what does a short carbon chain mean for the hydrocarbon?
it will be more runny and less viscous
more volatile (turns into gas at lower temp)
lower boiling point
more flammable
what is the word equation for complete combustion?
hydrocarbon+oxygen=carbon dioxide+water
what happens to the carbon and hydrogen during combustion?
they are oxidised
what is crude oil?
a fossil fuel
how does fractional distillation work?
the oil is heated until most of it has turned to gas which enters a fractionating column
in the column there is a temp gradient
longer hydrocarbons have high boiling points - they condense back into liquids and drain out of the column early on when they are near the bottom
shorter hydrocarbons have a lower boiling point and condense and drain out much later on near the top of the column
crude oil ends up separated out into different fractions each containing a mixture of hydrocarbons that all contain a similar number of carbon atoms so have similar boiling points
why do we crack long chain molecules?
they are not as useful as short chain molecules
what does cracking produce?
alkenes
what are alkenes used as?
a starting material when making lots of other compounds and can be used to make polymers
how can bromine water be used to test for alkenes?
when orange bromine water is added to an alkane no reaction will happen and it will stay bright orange
if bromine water is added to an alkene a reaction will occur resulting in a colourless compound being produced
