C6.2 Alkanes Alkenes Flashcards
Alkanes
HOW ARE THEY LART OF A HOMOLOGOUS SERIES.
Saturated hyrdocarbins
- form a homologous series because they have features in common
- follow a general formula = Cn H2n +2
- single covalent bonds used = saturated
- differs by a CH2 group
They do combust to form co2 and water, but also incomplete combustion to form carbon monoxide and water.
Carbon, soot carbon particulates can also be produced
Alkenes
How they follow a homologous series
Is methene possible?
Alkenes homologous because
- follow generalnformula = Cn2n
- have a functional group = where a bind of elements determine its properties. ( c- c double bind)
- differ by cH2
Unsaturated, the c-c double bind can break and form binds with other atoms
NO METHEN PE POSSIBLE
Remmeber at all times a carbon must bind with 4 things
How to test for alkenes
@) add bromine water, alkene will decolourise the bromine water if it is alkene (this is halogenstion) and because they can open a bond.
Goes from krsngebtincolourless ifnalkene
B2 + c2h4 = b2c2h4
TBIS dibromerhane
Methane because all of it is full now, cnnh2n + 2
Cracking
When alkene becomes alkene and ethene, used sfter seprsting alkanes in crude oil
1) need high temp and catalysts
Happens so we can make more shorter chain alkanes which are more easy to ignite and in higher demand. Alekenes dna then be euthernjyrdorgenwted to form alkanes or used in addition polymerisation
What makes a homologous series homologous
1) generals Formular
2) functional group / react in similar ways
3) differ by a ch2 groups
2 is basically 2 things
What is a functional group?
Atom, groups of atoms, type of bond that determines the chemical characteristic reactions that happen of an organic compound
What is difference between displayed , molecular and structural Formular ?
1) displayed is draw it out properly
2) structural is based on how it looks ordered like that
3) molecular is just like c4h10
What can the ability of having a CARBIN double in aliens allow them to do with hydrogen and what catalyst is needed
Addition resctions in the presence of hydrogen with nickel catalyst to for, an alkane. (Hydrogenation maybe?)
Alcohols
What can thy do to form something else
What do they react with to make an ester
1) cn2n+1 OH, Functional OH
2) OH oxidised means alcohols can be oxidised To firm carboxylic acids.
3) also take part in combustion
4) alcohol + caroboxylic = ester
Organic
Compounds means it has carbons in it
Carboxylic acids
Is there a double bind?
How are they made
What are their reactions typical like
What do they join with to make an Ester or amide
Homologous 1) cool functional 2) formula = cn-1 2n-1 Cooh 3) remember double bind c with o 4) oxidise alcohol to make it 5) reacts the same way acids so, 6) alcohol + cabrixhlic = Ester Amine + carbiyckic = amide
How are carboxylic acids made?
Also understanding
What is the oxising agent (2 things)
Also what happens in the colour change and why!!
- basically carboxylic acids become oxidised to form an alcohol so they gain oxygen
1) for example, an oxising absent of potassium manganite (7) can be added to ethanol. This oxising agent IS acidified with a little DILUTE SULFURIC ACID.
2) then warm it in a water bath
3) then a colour change occurs because manganite (7) ions are purple and become REDUCED to pale pink managnaes (11) ions when the acidified potassium managnateb(7) oxidises ethanol to ethanol companies acid
Purple managnatebions become reduced into pale pink manganese (2) ions.
As carboxylic acids are typical of acids what reaction do they undertake?
How do you name the salts with carboxylic acids?
1) metals with acid = salt + hydrogen gas
2) acid+ alkali = salt + water
3) acids + metal carbonate = salt + water + CARBIN dioxide
Metal + say Ethan + OATE
so potassium methanoate for example
Where does crude oil come from
It is our main source if?
What makes it a non renewable source ?
Buried remains of marine organisms lived millions of years ago making it a fossil fuel . Over millions years under high temp and pressure they become crude oil which can be extracted
Hyrdocarbins
It is being used faster than made
What happens if there are more CARBOn atoms in an alkane ? (Important 3)
1) the stinger the intermolecular forces as there are more contact pints and thus more intermolecular
2) thus higher boiling and melting
3) also bigger molecules ofc
How is crude oil extracted 6 marker mr choo
What about some of the gasses
1) crude oil is heated and a temperature gradient is thus established (this is where it’s hotter at the bottom and cold at the top)
2) the alkanes evaporate and rise up the column
3) the alkane vapours cool as they rise up the colouring
- different alkanes will have different boiling points
4) once they reach a part where the temperature is less than the boiling pint (or ince they hit their feeding pint ), they CONDENSE into liquid
5) these are then collected in separate tanks , these separate sections are called fractions which contain many alkanes of similar band
2) refinery gases have the lowest boiling pints and reach the top without even condemning snd Exit in gas form. Bitumen similarly is almost solid at rt
Again for fun
1) crude oils are heated and temp gradient established
Why is fractionally distalkrion used
What is the use of crude oil?
Why are small alkanes more desierbwle ? (3) IMPORTSNT
What are big alkanes used for then
)
electricity heating , fuel for transport, raw materials to make plastics infrastructure
2) require less oxygen, so combust completely, less energy to ignite = HIGHLY FLAMMABLEM, also flow eastern
3) infrastructure and cracking to make alkenes and alkanes and thus
What does cracking Dom?
What is needed to make it happen ? What does allow it to do?
Why is it done
Chemical reaction that converts large alkane molecules into smaller alkanes and alkenes
Octane c8h18-> Propene c3h6 snd pentane c5h12
2) high tem 600-700 and hot catalyst of alumina or silica , which MAKE THE CIVALENT BINDS BREAK
3) to make smaller alkanes which are higher in demand and alkenes ti make plastics in ploymer form
Alkene used for?
Plastics
Hydrogenation (back to alkanes
Hydration?
How does practices of making paraffin Hallen?
1) liquid paraffin is heated into gas form so it can react with the ctaksydt (this is thermal decomposition)
2) now you get an alkane as liquid and alkene as gas as alkanes will always have higher intemroelfulwrnbinds due to them being able to be stacked on each other
Additon polymerisation
What is it
What does it require
What need to start it aswell
1) additon polymers are made from many unsaturated monomers that joint together to make a polymer , the. Kromer sundergi additon reactions to join
2) will usually require high pressure and catalyst
3) open brackets and binds, n
4) an initiator chemical that starts the chain off
Use water bath as they flammable, fume hood and googled if needed
Dna structure and bindings
Nucleotides join to make dna
2) deoxyribiose of one joins with the phosphate if one on top
3) hydrogen binds formed between comolentwry based
Amino acids for Proteinen
20
2) has functional group on each end so as monomers they can undergo condensation polymerisation still
Amine Gounods nh2
Amide group is conh
And polymerisation of amino acids would be -( nh-block-co)-
Basically amino acids also have carboxylic acids group at the others side
Carbohydrates, difference between simple sugars and complex carbs ?
1) compounds of carbon, hydrogen and oxygen USED BY LIVING THINGS TO PROVIDE ENERGY
2) simple SUgars deoxyribios and sucrose
Complex are starch, which are made up of other simple sugars such as glucose
