Organic chemistry Flashcards
(24 cards)
what is crude oil
crude oil is a mixture of compounds ,
finite source- cannot be replaced as it is used up
what is hydrocarbon
a compound made up of exclusively hydgrogen and carbon atoms
what are alkanes
saturated hydrocarbons of a general formula
what is a homologous series
series of compounds with same general formula , same functional groups and similar chemical properties
describe the combustion of hydrocarbons
- exothermic reaction occurs. when hydrocarbons are reacted with oxygen
- complete combustion produces carbon dioxide and water
- incomplete combustion produces carbon monoxide and water
describe the physical properties of alkanes
. first few in series are gases, then change to liquids , then to solids.
.boiling points and viscosity increase as molecules get bigger
.poor reactivity
explain how fractional distillation of crude oil takes place
1.crude oil is heated and vaporised
2.vapor rises up the fractionating column
3. the column is hotter at the bottom and cooler at the top
4.hydrocarbons cool as they go up the column and condense at different heights,as they have different boiling points
5.large molecules,high boiling points,collected at the bottom
6.small molecules . low boiling points collected at the top
7. this gives fractions which , can be used in various ways.
what is cracking
when large hydrocarbons are thermally broken down into smaller and useful molecules
what type of reaction is cracking
thermal decomposition
what are the conditions for cracking
. reactant heated to vapor, passed over a hot catalyst(catalyic cracking)
.heated to vapor, mixed with steam and heated to high temperatures(steam cracking)
how are the products of cracking used
the products are alkanes and alkenes = used as polymers and starting materials for synthesis
what is an alkene
unsaturated hydorcarbon
what is the test for alkenes
add bromine water. colour changes occurs from orange to colourless
describe the combustion of alkenes
they burn with smoky flames due to incomplete combustion
describe addition reactions of alkenes
with hydrogen- requires a higher temperature and a nickel catalyst
with steam- required high temperature, pressure and catalyst
what is an alchahol
an organic compound that contains an -OH functional group
state charachteristics of methanol,ethanol,propanol, and butanol
.dissolve in water to form an nuetral solution
.react with sodium to form hydrogen
.burn in oxygen
.react with carboxylic acids in prescence of acid catalyst to form esters.
what are some uses of alcohols
.fuels
.solvents
.drinks
state the conditions required for fermentation of glucose and state the equation of the reaction
.30 degrees celcius
.aqueos solution of the glucose
.abscense of air
.yest added
state charachteristics of carboxylic acids
.disolve in water to form n acidic solution
.react with metal carbonates to form carbon dioxide
.react with alchahols with an acids catalysts to produce esters
.react with metals to give off hydrogen gas
what is a polymer , how do molecules containing C=C bond form polymers
. A polymer is a long chain of molecules, which is made by lots of smaller molecules joining together
.C=C bonds open up and many smaller molecules join together to form a chain.
give 3 examples of addition polymers and their uses
.Polythene-plastic bags
.chlorotheone-water pipes
what is a repeating unit of a polymer
.it is a smllest structure which,uponnumerous translations , yeilds the structure of the polymer
What is DNA, describe its role and structure
.DNA is a material that makes up chromosomes- cell structures that store genetic information.
.DNA is made up of two polymer chains that are held together in a double helix
.Each polymer chain , can be made up from 4 different monomers-nucletoids.
