Introduction To Organic And Alkanes 3.3.1+2 Flashcards
How many strong covalent bonds can carbon form
Are they polar or non polar
4
Non polar
What is nomenclature
Name of an organic compound
Define functional group
An atom or group of atoms in an organic molecule responsible for the characteristic reactions of that molecule
What is a Homologous series
A set of compounds with the same functional group, the Compounds differ in length
What is the prefix for 1 to 10 carbon atoms
1 meth
2 eth
3 prop
4 but
5 pen
6 hex
7 hept
8 Oct
9 non
10 dec
What is the skeletal formula used for
Complex organical molecules
What do the straight lines in a skeletal formula represent
C-C bonds
What is the general formula for Alkane
CnH2n+2
What is the general formula for alkene
CnH2n
Samsung notes
Nomenclature
What are two types of isomers
Structural isomers and stereoisomers
What are 3 types of structural isomers and explain them
Chain isomers: More than one way of arranging carbon atoms in the longest chain
Position isomers: Same functional group but it is attached to the main chain at different points
Functional group isomer: Compounds with the same molecular formula but different functional group
Define structural isomers
Moelcules with the same molecular formula but different structural formula
Are the chemical and physical properties in chain isomers similar or different
What are the properties of chain isomers
Similar chemical properties but slightly differnt physical properties. The more branched the isomer, smaller the surface area, weaker the Van der Waals forces between molecules- lower the boiling point
What are the 4 pairs in a functional group isomer
Carboxylic acid + Ester
Ketone + Aldehyde
Alkene + Cycloalkane
Alcohol + Ether(Oxygen between two carbon atoms)
Cyclo Samsung notes
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Define stereoisomers
Molecules with the same structural formula but with atoms/bonds/groups arranged differently in space
Where do stereosiomers occur
They only occur in alkenes
Why do stereoisomers arise [2 marks]
Restricted rotation around the planer carbon-carbon double bond
Two different groups attached to each C of the C=C bond
When do you use E and Z when naming a stereosiomer
E when the two groups are on opposite sides
Z when the two groups are on ze zame zide
What does CIP stand for
Explain it
Cahn-Ingold-Prelog priority rule
-Look at atom directly bonded with C
-Atom with highest atomic number has highest priority
-If atom bonded to C is same, look at next atom bonded to C to work out highest priority
When does a molecule not show stereoisomerism
-Each of the C in the C=C bond are not bonded to at least one substituent group
-If one of the double bond carbons have 2 C-H bonds
Stereoisomers Samsung notes
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Are alkanes Saturated or Unsaturated hydrocarbons
Saturated
What are some uses of alkanes
Fuels
Lubricants
What is the main source of alkanes
Crude oil
What shape do alkanes form
Tetrahedral shape
What type of isomers exists in alkanes
What is the relationship beyween chain length and number of isomers
Chain isomers which is a type of structural isomerism
The number of isomers rises rapidly as chain length increases
What is the state of different chain alkanes at room temperature
Short alkane chains C5are gases
C5 to C17 are liquids
Longer carbon chains are waxy solids
Are alkanes polar or non polar and why
Non polar because difference in electronegativity betweeb carbon and Hydrogen is very small
How many intermolecular forces exist within alkanes and what are they
One which is van der waals forces
In an alkane, explain how Mr values of molecules and mp and BP are linked
The higher the Mr, the stronger the VDW forces, mp and BP increases
Do branches alkanes have a higher or lower mp and BP that straight chain moelcuels and explain why
Branched alkanes have lower mp and BP than straight chain molecules with the same number of C atoms becuase branched alkanes have a smaller surface area, straight chains packed together more closely, decreases strength of VDW forces, less energy needed to overcome the force
What substances are alkanes soluble and Insoluble in
Insoluble in water
Soluble in non polar liquids
What substances are alkanes soluble and Insoluble in
Insoluble in water
Soluble in non polar liquids
What is the reactivity of alkanes
Relatively unreactive
Do not react with acids, bases, oxidising agent and reducing agents
Explain two substances alkanes do react with
Burn and react with halogens under suitable conditions
Burn in oxygen (plentiful supply) to form carbon dioxide and water
Describe crude oil
It is a rich and varied mixture of over…
Dark yellow to balck in colour and is a sticky viscous liquid
…180 carbon based Compounds
How does crude oil form
Remains of plants and animals covered in mud, silt and sand over millions of years
High pressure causes it to become oil
In Fractional distillation, what is a fraction
A mixture of simialr chain length hydrocarbons so have similar boiling points
What is cracking
What are the economical reasons for cracking
What bond does this break
Process is which long chain hydrocarbons molecules are broken into shorter chain molecules
-Smaller chain mkelcuels are higher in demand and products from cracking are more valuable and useful
C-C bonds
Describe the process of thermal cracking
Why does this produce free radicals
Long chain meolcurs are heated to very high temperatures (700K - 1200K) and high pressures (up to 7000kPa) for a short duration
When C-C bond breaks, one electron from the pair goes to each C atom, shorter chains are produces which each have a carbon atom with an unpaired electron, these are called free radicals
What is broken during Fractional distillation
When can these reform
Van Der Waals forces
Condensing
Explain the process of Fractional distillation in crude oil
-Crude oil is heated in a furnace until a portion vapourises
-Liquid vapour mixture passes up fractionating tower
-The fractionating tower is cooler at the top and hotter at the bottom(negative temperature gradient)
-Shorter chains are collected at the top of the tower which is cooler as they have lower BP
-When a substance reaches a layer that is cool enough, it condenses and is piped off
-These distillates are known as fractions
-A fraction is a group of Compounds that having similar BP and are removed at the same level of a fractionating tower
In nomenclature, what is the least to highest priority functional group
Halogens, alkyl groups, alkenes, other functional groups
What are the products of thermal cracking
Why are alkanes duration in thermal cracking conditions for a very short time (1 second)
Produces a high proportion of alkenes
To avoid too much decomposition to just carbon and hydrogen
Describe catalytic cracking
Long chain alkane is heated under pressure in the presence of a zeolite Catalyst
Temperature- 450 degrees calcium
Pressure - 1 to 2 atmospheres
Time - 2 to 4 seconds
During catalytic cracking, what is being broken
Carbon to carbon bonds in alkane molecules
What is a zeolite Catalyst and what is its adaptation
An acidic material made of aluminium oxide and silicon dioxide
Honeycomb sturtcure to increase surface area which increases rate of reaction
What are the products of catalytic cracking
Branched alkanes cycloalkanes aromatic Compounds
This method usually produces motor fuels
Cracking Samsung
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What are fuels
What are used as fuels
Substances that release heat energy when they go through combustion
Alkanes
When alkenes go through combustion, what is the relationship betweeb number of carbons and amount of heat energy released
The more carbons, the more heat energy released
Give some examples of alkane fuels
Methane
Propane
Butane
Petrol
Paraffin
What are two types of combustion
Complete combustion
Incomplete combustion
What are the products of complete combustion
Carbon dioxide and water
When does incomplete combustion occur
When there is a limited supply of oxygen
What are the products of incomplete oxygen
What are the products if there is even more limited oxygen
Carbon monoxide and water
Carbon and water
Name some atmospheric pollutants
Carbon monoxide
Nitrogen oxides
Sulfur dioxide
Carbon particulate
Unburnt hydrocarbons
Carbon dioxide
Water vapour
How does an internal combustion engine work
Where do the products of combustion exit
They work where a small amount of fuel and large amount of oxygen is drawn into the combustion chamber
Mixture is compressed and ignited with an extreme temperature spark
The mixture bruns explosively, forcing movement of the engine parts
The products of combustion exit via the exhaust
What do catalytic converters do
The internal combustion engine produces many pollutants which can be removed using catalytic convertors
What is a catalytic converter made from
Honeycomb made of ceramic material coated with platinum and rhodium metals and these metals are Catalysts
Why is the catalyst coated on ceramic honeycomb on a catalytic converter
Bigger surface area
Increases rate of reaction
Removes more of the gases
Ensures complete reaction
Why is a thin layer of metal used on the ceramic honeycomb
To reduce the amount of metals needed
Increase surface area
In a catalytic converter, as the pollutants pass over the catalyst, they react with eachother to form less harmful products
Give two of these reactions
Carbon monoxide + Nitrogen oxide -> Nitrogen + carbon dioxide
Hydrocarbons + Nitrogen oxide -> Nitrogen + carbon dioxide + water
What are the impacts of acid rain
Destroys trees and vegetation
Corrodes building
Kills fish in lakes
How can sulfur dioxide be removed and how is this done
Why are these specific reactants used
Flue gas desulfurisation
Calcium oxide and calcium carbonate are used to remove sulfur dioxide in an acid base reaction to produce gypsum
These reactants are used as they are basic so they can neutralise the acid
Explain the greenhouse effect
Infrared radiation from the sun passes through mahers of gas in the atmosphere to hit the earth, which warms the earth up
The infrared radiation from tbe earth travels back through the atmosphere where some is prevented from escaping into space by greenhouse gases
What is the importance of the greenhouse effect
It keeps temperatures on Earth warm enough to support life
What is global warming and what is it caused by
The increasing average temperature of the atmosphere at the surface of the earth
It is caused by a chnage in the concentration of carbon dioxide in the atmosphere
Why is global warming increasing recently
More fuels are burnt so more water and carbon dioxide released so more heat being trapped so earth’s temperature increases
When is sulfur dioxide produced
Combustion of hydrocarbons containing sulfur
In a halogenoalkane, why is the C-X bond polar
The halogen atom is more electronegative that the carbon atom
As you go down group 7, what happens to the polarity of the bond in he haolgenalkane and why
The C-X bond becomes less polar because the electronegativity of the halogen atom decreases
How is BP and carbon chain length linked
Boiling point increases as carbon chain length increases
How is van der waals forces and relative molecular mass linked
Van der waals forces increases as relarive molecular mass increases
Do dipole dipole forces or van der waals forces affect the BP of a molecule the most
Van der waals forces
What is special about halogenoalkanes solubility in water and why
The carbon - halogen bond is polar but they are Insoluble in water, there are Hydrogen bonds in water and polar bonds can’t overcome Hydrogen bonds
Where are halogenoalkanes soluble
Organic solvents
What are some uses of halogenoalkanes
Dry cleaning Fluids and degreasing agents
What are the products in the chlorination of alkanes
Mixture of chloroalkanes and Hydrogen chloride gas
What would you observe in the chlorination of alkanes
Misty white fumes
In step 2, propagation in chlorination of alkanes, what are the two equations when CH4 forms CH3Cl
What is the 3 different termination equations that could occur
●Cl + CH4 => HCl + ●CH3
●CH3 + Cl2 => CH3Cl + ●Cl
——————————————
●CH3 + ●CH3 => C2H6
●CH3 + ●Cl => CH3Cl
●Cl + ●Cl => Cl2
