organic chemistry Flashcards
what does the prefix tell
the prefix tells you how many carbon atoms are present in the longest continues chain in the compound
what does the suffix tell you
- ane: compound is an alkane
- ene: compound is an alkene
- ol: alcohol
- oic acid: carboxylic acid
what is a hydrocarbon
any substance that contains only carbon and hydrogen
what is catenation
the self linking ability of atoms
what is the catenation of carbon
one carbon molecule can make up to 4 bonds
what are the fossil fuels
crude oil, oil and natural gas
what do fuels do
fuels release energy upon being burned
what does natural gas consist of
methane
what does petroleum consist of
petroleum is essentially crude oil and is a mixture of hydrocarbons that can be seperated into its useful fractions by fractional distillation
fractional distillation of petroleum process
- petroleum is heated and turned into a gas before it is sent to the fractionating column to remove its impurities
- the molecules in each fraction have similar properties and boiling points, which depend on the number of carbon atoms in the chain
- the boiling point and viscosity of each fraction increases as the carbon chain gets longer
- temperature increased down the fractionating column because more energy is needed to break the longer carbon chains
what is a homologous series
a series or family of organic compounds that have similar features and chemical properties due to them having the same functional group
general characteristics of homologous series
- compounds have the same functional group
- they have the same general formula
- the have similar chemical properties
- they have different physical properties
- there is a difference of a CH2 group between consecutive members of a homologous series
what are structural isomers
compounds that have the same molecular formula but different structural formulae due to the different arrangement of their atoms
what are the two types of structural isomers
chain and position
what is chain isomerism
when the structure of the carbon chain diffrs
what is position isomerism
when the postion of the functional group differs
what is the general formula for alkanes
CnH2n+2
what are alkanes
alkanes are saturated hydrocarbons which means that they do not have any carbon double bonds or rather they all have single bonds
names and formulas of alkanes
http://www.sparknotes.com/chemistry/organic2/alkanes/section1/
combustion of alkanes
alkanes are generally unreactive, however they undergo combustion when they are burned with oxygen, this produces carbon dioxide and water and releases energy
what is the general formula of alkenes
general formula : CnH2n
functional group of alkenes
C=C (double bond)
what are alkenes
they are unsaturated hydrocarbons
difference between alkane and alkene
-molecular structure: saturated hydrocarbons have no double bonds in their structure while unsaturated hydrocarbons have at least one C=C double bond
how to test for differences between saturated and unsaturated hydrocarbons
aqueous bromine water: When added to unsaturated hydrocarbons, the colour of the solution changes from orange to colourless/ The bromine atoms add across the C=C double bond hence the solution no longer contains the orange colours bromine. THis is called bromination. On the other hand, when added to saturated hydrocarbons, there is no colour change
what is cracking of alkanes
- cracking of larger alkanes is done because lower alkanes and alkenes are more useful
- cracking of larger alkanes produces an alkene and can produce lower alkanes and hydrogen gas as well
what kind of reaction is cracking
cracking is both thermal and catalytic. This means it requires heat and a catalyst. This process breaks covalent bonds in the molecules, causing thermal decomposition reactions
addition reaction of alkenes with bromine water
when added to alkenes, the colour of the solution changes from orange to colourless. The bromine atoms add across the C=C double bond and hence the solution no longer contains the orange coloured bromine
addition reaction of alkenes with hydrogen
- alkenes also undergo addition reactions with hydrogen in which an alkane is formed
- these are hydrogenation reactions and occur at 200C using a nickel catalyst
addition reaction of alkenes with steam
alekens also undergo addition reactions with steam in which an alcohol is formed SInce water is being added to the molecule it is also called a hydration reaction. THe reaction occurs in the following conditions: (temperature: 350C pressure: 60-70atm catalyst: concentrated phosphoric acid)
what is addition polymerisation
- addition polymers are formed by the joining up of many small molecules called monomers
- additoin polymerisation only occurs in monomers that contain C=C bonds
- one of the bonds in each double bond breaks and forms a bond with the adjacent monomer
general formula for alcohols
CnH2n+1OH
functional group of alcohols
OH
name and formulas of alkenes
https://d2gne97vdumgn3.cloudfront.net/api/file/JlHA0rwCQ8ar92aeIPwi
names and formulas of alcohols
http://chemistrymsq11.blogspot.com/p/9an-introduction-to-organic-chemistry.html
ethanol
ethanol (C2H5OH) is one of the most important alcohols
manufacture of ethanol
- the hydration of ethene with steam
- or the fermentation of glucose by yeast produes ethanol
fermentation of glucose by yeast temperature and pressure
- optimum temperatures is 37 deg cel
- as more alcohol is produced, themperature increases, so it has to be colled down so that the enzymes in the yeast do not get denatured
- pressure of 1atm
fermentation of glucose by yeast type of raw materials
renewable as glucose comes from plants
fermentation of glucose by yeast type of process
batch (stop-start)
fermentation of glucose by yeast labour
lots of workers needed
fermentation of glucose by yeast rate of reaction
slow
fermentation of glucose by yeast purity of product
impure (needs treatment)
fermentation of glucose by yeast energy needed
a lot
hydration of ethene type of raw materials
non-renewable (ethene from crude oil)
hydration of ethene type of process
continous (runs all the time)
hydration of ethene labour
few workers needed
hydration of ethene rate of reaction
fast
hydration of ethene conditions needed
- high temperature (450-800C)
- high pressure (60-70 atm)
hydration of ethene purity of product
pure (no by-products made)
hydration of ethene energy needed
a lot
uses of ethanol
- can be used as a solvent and a biofuel to release energy
- can be burnt in oxygen to produce carbon dioxide and water and release energy
carboxylic acid general formula
CnH2n+1COOH
functional group of carboxylic acid
-COOH
ways to make carboxylic acid
- oxidation of ethanol by fermentation (the microbial oxidation of ethanol will produce a weak solution of vinegar /ethanoic acid)
- oxidation of ethanol with acidified potassium manganate (VII) will produce ethanoic acid
formula for oxidation of ethanol by fermentation
C2H5OH + O2 -> CH3COOH + H2O
ethanoic acid properties
- is a typical weak acid
- they react with alkaline solutions, turn blue litmus red and form salts called ethanoates
- dissociates slightly in water, producing a mildly acidic solution
- its reactions with carbonates, hydroxides and metals are similar to other acids
- it has similar properties to other weak acids
what is esterification
- in the presence of catalysts, alcohols can react with carboxylic acids to produce an ester and water
- this is a reversible reaction
- the OH group is removed from the acid while the H is removed from the alcohol
what is an ester
- esters are compounds with the functional group R-COO-R
- they are sweet smelling oily liquids used in food flavorings and perfumes
catalysts for esterification
catalysts include concentrated sulfuric acid
names of esters
- the first part of the name indicates the length of the carbon chain in the alcohol and it ends with the letters ‘-yl’
- the second part of the name indicates the length of the carbon chain in the carboxylic acid and it ends with the letters ‘-oate’
what are polymers
- polymers are large molecules built up from small units (monomers)
- different polymers have different units and/or different linkages
- some polymers contain two or more different types of monomer units
- different linkages exist, depending on the monomers and type of polymerisation
uses of plastic
plastic bags, bottles, food packaging, ropes, carpets, plastic sheets, artifical leather
uses of man made fibres such as nylon and terylene
- nylon is used to produce clothing, fabrics, nets and ropes
- terylene is used extensively in the textile industry and i soften mixed with cotton to produce clothing
problems caused by non-biodegradeable plastics
- stay in the environment for a long time
- take up space and fill landfills
- cause visual pollution
- produce toxic gases when burnt
- plastic waste has been spilling over into the seas and oceans and is causing huge disruptions to marine life
- these plastics can choke small animals and even enter soil and choke the roots
addition vs condensation polymerisation
- in addition polymerisation no molecule is removed, but in condensation polymerisation a small molecule is removed, usually water
- condensation polymerisation usually involves two different monomers, each one having a functional group on each end. On the other hand, addition polymerisation uses only one monomer
- in the former no by-product is formed but in the latter water is produces as the by-product
addition polymerisation of alkenes drawing
- identify the repeating unit in the polymer
- change the single bond in the repeat unit to a double bond in the monomer
- remove the bond from each end of the repeating unit and the subscript n
Condensation polymerisation of polyamides
- amide linkage
- amide linkage is formed with the subsequent loss of one water molecule per link
- each -COOH group reacts with another -NH2 group on another monomer
condensation polmerisation of polyester
- ester linkage
- each -COOH group reacts with another -OH group on anther monomer
- an ester linkage is formed with the subsequent loss of one water molecule per link
protein condensation polymerisation
- same (amide) linkages as nylon but with different units
- the monomers are called amino acids
- amino acids consist of one NH2 group and one COOH group
- proteins can also be hydrolysed by the addition of water in acidic or alkaline conditions to amino acids
- enzymes can also be used to hydrolyse some proteins at room temperature, mimicking natural bodily processes
what are complex carbohydrates
-consists of a large number of units that cnsist of 2 -OH groups which are joined together by condensation polymerisation
hydrolysis of complex carbohydrates (e.g.starch)
done by acids or enzymes to give simple sugars
simple carbohydrates
called monosaccharides and are sugars such as fructose and glucose
complex carbohydrates
- called polysaccharides such as starch and cellulose
- condensation polymers formed from simple sugar monomers
what is fermentation
simple sugars can be fermented to produce ethanol and carbon dioxide using bacteria or yeast
how to use chromatography to identify the products of the hydrolysis of carbohydrates and proteins
- both carbohydrates and protein monomers are colourless so locating agents must be used
- a technique called 2D paper chromatography is used as some simple sugar and amino acids have the same Rf.
- these can be compared to previously found Rf values to identify the simple sugars and amino acids
