Organic Chemistry Flashcards
How is ethanol made
Fermentation or hydration of ethane
What raw materials are needed for fermentation and conditions and speed
Sugar from plant material , yeast and water. Yeast added to sugar solution and left in 30-40 degrees in the absence of air. Very impure ethanol produced and slow reaction several days for each batch glucose -yeast-= ethanol and carbon dioxide
What raw materials are needed for hydration of ethene and pressure and speed and product
Ethene and steam more purer than fermentation more efficient process but needs high temperature and high pressure a stream of reactants is passed over the catalyst (phosphoric acid)
What are structural isomers
Molecules with the same molecular formula but different structural formula
What is a saturated hydrocarbon
Contains the maximum possible number of hydrogens for a given number of carbons
Pollutant carbon
Formed by incomplete combustion of hydrocarbons harmful to tissues and lining of nose lung and threat . Carcinogen
Pollutant carbon monoxide
Incomplete combustion of hydrocarbons. Haemoglobin have a greater affinity for carbon monoxide and oxygen and carbon monoxide reduces the oxygen carrying capacity of the blood leading to unconsciousness and death
Sulfiric acid
Produced by hydrocarbon fuels naturally containing sulfir when they burn sulfur oxidises to sulfur dioxide and dissolves in water vapour of clouds to from sulphuric acid thus makes rain acidic which damages buildings and kills fish
Oxides of nitrogen
High temperature combustion of hydrocarbons such as in car engines. Reacts with oxygen leads to acid rain
When will alkanes react with bromine
Aren’t very reactive because of 4 strong covalent bonds so will only react with bromine when given energy by uv light and then does substitution reaction where bromine replaces hydrogen
What are hydrocarbons
Compounds containing only carbon and Hydrogen
What is crude oil
Fossil fuel , mixture of hydrocarbons, viscous dark coloured, hydrocarbons can be easily separated with the properties unchanged. A mixture is 2 or more elements / compounds that are not chemically combined
How is crude oil separated
Fractional distillation. Fractions are groups of compounds with similar boiling points. Crude oil enters at the bottom vapourised by the burner mixture of gases rise until they reach their boiling points and condense and leave the fractional distillation column as a liquid
What happens to boiling points
They increase as the molecules get bigger. As does viscosity and ease of ignition and color darkens
Why does boiling point increase as fraction gets bigger
Has more intermolecular forces that need to be broken . As fraction size increases so does the strength of the intermolecular forces so more energy is required to overcome the forces
What does incomplete combustion of alkanes lead to
Carbon monoxide and water
What is a homologous series
A series of compounds that can be described by a general formula
General formula of alkanes
Cn h2n +2
How do boiling points of alkanes increase with carbon chain
Length of carbon chain increases boiling point
What alkenes contain and what’s their general formula
Cn h2n
Contain one double bond between adjacent carbon atoms
What is cracking
Hydrocarbons are heated and passed over a catalyst to break them down due to higher demand for smaller chains of alkanes
Why are large hydrocarbons less useful than short ones
Harder to ignite have higher melting and boiling points
What are two forms of cracking
Catalytic cracking at low temperatures and pressure uses a catalyst
Mineral wood soaked in paraffin oil is heated and passed through a test tube containing al2o3 passed through dekievery tube and gas of a smaller chain hydrocarbon is produced .the catalyst breaks the bond between the carbons
Thermal cracking
High temperatures and pressure
What kind of reaction is cracking
Thermal decomposition substance is broken down into smaller substances bubharv
Why should the first few bubbles of gas from the cracking not be collected and why is the paraffin heated
Because they will contain mostly air that has expanded due to heat.
Parrifin heated to vapoursie and reach its boiling point
How do you test for alkenes
Bromine gas goes colourless
What does cracking produce
An Alkene and an alkane
How do alkenes combust
Produce carbon carbon dioxide and water burn with a smokey flame and do incomplete combustion
What is a polymer
A long chain of small molecules called monomers covalently bonded together formed by addition polymerisation of alkenes
What is general formula of alchohols
Cn H2n+1 OH
Meth
1
Eth
2
Prop
3
But
4
Pent
5
Methyl
CH3 side chain
Ethyl
CH3 CH2 side chain
Why do boiling points if alkanes increase
Intermolecular forces get bigger as molecule gets bigger meaning more energy is needed to break the bonds
How do alkenes react with bromine
Addition reaction . Double breaks and bromine replaces the empty gaps and goes colourless
Why is it impossible to make pure alcohol by fermentation
Yeast is killed by it
What is dehydration of ethanol
Produces ethene . Mineral wool soaked in ethanol passed through Test tube with alumninuk oxide and is heated . Ethene collects at the end of delivery tube. Ethanol vapour is passed over hot aluminium oxide
What products condense first in the distialktor
Ines with higher boiling points
What are refinery gases
Not cold enough for them to condense mixture of methane, ethane and propane used as liquefied petroleum has for domestic heating and cooking
Gasoline (petrol
At around 50 degrees condenses. Mixture of hydrocarbons with similar boiling points is used as fuel
Kerosine
Boils at 190 used as fuel for jet air craft and domestic heating oil and paraffin
Diesel
250 degrees. Used for buses lorries some cars and some is cracked to produce more petrol
Fuel oil
330 used for ships boilers and industrial heating
Bitumen
Hydrocarbons that aren’t hot enough to boil remain as liquid and is a thick black material meted and mixed with rock chips to make the top surface of roads
Why are alkenes more reactive
Contain a carbon double bond which is weak
How does polymerisation work
Part of the carbon double bond is broken and the electrons in it join to neighbouring molecules . It happens at high pressure and temperatures with an initatiator .
What is poly ethene
Low density poly ethene is used as a thin film to make polythene bags as its flexible and not string
What is polypropne
Made of propene stronger than polythene used to make ropes and crates
What is poly chloroethene
Ethene molecule one hydrogen is replaced by a chlorrine. Polymerised to create PVC its string and ridgid used to make drainpipes and electrical insulation
How do you make nylon
Condensation reaction where each time two monomers combine a small molecule is lost .
A loss of water is formed . Nylon is formed by dicarboxylic acids and diamine
What’s nylon used for
Textiles fibres used in ropes
