Life Science Flashcards
Organic chemistry
the study of the preparation, reactions, properties, structure and composition of the carbon containing compound
Saturated compound
It is a compound where all the bonds in carbon atoms are single bonds
Hydro carbons
compound containing hydrogen and carbon atoms
give examples of hydrocarbns
alkanes and alkenes
example of a saturated organic compound
alkanes
Unsaturated compound
compound where the bonds in the carbon atoms are double or triple bond.
example of unsaturated compound
alkene
functional group
it is an atom or group of atoms that form the centre of a chemical activity in the molecule
homologous series
Group of organic compounds that have the same characteristics
what are the 5. characteristics that a the homologous series have
a. have same functional group
b. have same chemical properties
c. prepared with the same method
d. conform to same general formula
e. succesive members differ by -ch2 unit
Isomers
Organic compounds with the same molecular formula but different structural formula
types of isomers
a. chain isomer.
b. functional isomers
c. postional isomers
General fromula for alkanes
CnH2n+2
normen clature
the naming of organic compounds
describe Physical properties of alkanes
Physical properties gradually change as number of atoms increase due to increase in strength of london forces
Boiling points of alkanes
branched alakanes have a less boiling pount that straight chained alkanes because branched alaknes have less surface area of contact between molecule resulting in weak london forces.
Sources of alkanes
a. natural gas.
b. crude oil.
c. petroleum
what are the physical properties of alkanes
a. colourless
b. less dense than water.
c. non polar molecules which means they are soluble in non polar solvents.
d. they are flammable
alkanes show which isomerism
chain and postional
Chemical properties of alkanes
Alkanes are unrecative hydrocarbons beacuse they are saturated organic compounds.
what are the reactions alkanes goes through
combustion and subtitution with halogens
what is combustion of alkanes
alkanes burn well with oxygen producing carbon dioxide, water and heat energy. which is why they are used as fuels.
Alkanes reacation with halogen
it is called substitution then the specific thing is halogenation.(hydrogen atoms are replaced by halogen atoms)
Alkanes react with halogens in the presence of what?
presence of uv lights producing hydrogen halides and halogen alkanes
use of alkanes
fuel.
Exxplain the physical properties of alkenes
Physical properties of alkenes change gradually as carbonatoms increase due to increase in strength of london forces
Boiling points and melting points of alkenes
Branched alkenes have low melting points and low boiling points than straight chain alkenes because they have less surfcae area contact between molececules which results in weak london forces
what isomerism does alkenes show
chain, functional,position isomeism
Sources of alkens
a. cracking
b. dehydraton of alchol using concenrated sulfuric acid(deydration and elmination)
c. halogen alkanes react with alcohlic sodium hydroxide or potassium hydroxide(eliminaation and dehydrohalogenation
what is cracking
breaking down of long chains of alkane molecule using heat and catalyst into shorter chains and more useful ones
cracking produces shorter alkanes and alkenes
Chemical properties of alkenes
they are reactive beacuse they are unsaturated, the double bonds act like source of elctrons therefore they undergo addition reactions.
Alkenes undergo which 5 reactions
a. combustion
b. addition of hydrogen.
c. reaction with steam
d. reaction with bromine
e. reaction with hydrogen halides
decribe the reaction of alkene and hydrogen
it is an addition reaction.
specific is hydrogenation
alkene react with hydrogen in presence of heat pressure and catalyst.
describe reacation of alkene with steam
alkenes reacts with steam in presence of heat forming alchol, catalyst, phosphoric acid
addition reaction and hydration
Describe reaction of alkene and bromine
Alkenes reacting with bromine water decolourises the water.
process is used for distingishing alkanes and alkenes
it tests the unsaturation in organic compounds
bromine shake with alkenes watere becomes colourless.
alkanes cannot
addition reaction or halogenation
Reaction with hydrogen halide
alkene reacts with hydrogen halide forming halogen alkanes
Halogen alkanes
1 or more hydrogen atoms of alkanes are replaced by a halogen
what are the sources of halogenalkanes
a. reaction between hydrogen halides and alkenes
b. reaction with alkane and hydrogen in prsence of uv light
c. alkenes react with halogens.
Physical properties og haloalkanes
B.P increases due to increase in van der waal forces. halo alkanes have a higher boiling point than alkanes and alkenes because they are polar molecules therefore they have strong van der waal forces than alkanes and alkenes of the same length.
Chemical properties of haloalkanes
very reactive due to presence of halogen in the molecules
reaction happens on carbon carry the halogen atom
undergo substitution reaction where halogen atom is replaced by othe atoms
Reaction that haloalkanes go through
a. reaction with water and koh or naoh
b. elimination reaction
describe the reaction of water and koh or naoh for haloaknaes
water and koh an naoh react forming alchols(hydrolosis) and subtituition
elimination reaction
reaction is undergone is presense of koh an naoh.
hydrogen and halogen atoms are removed from carbon resulting in formation of double bonds between carbons (dehydrohalogenation)
Alcohol/hydoxyl compounds
Oh bonded to carbon function group OH
