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50 Cards in this Set
- Front
- Back
Arenes |
Aromatic hydrocarbons with one or more benzene ring |
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4 examples of products benzene can produce. |
Explosives, dyestuffs, pharmaceuticals and detergents |
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Two natural sources of arenes |
Crude oil and coal |
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Two natural sources of benzene |
Volcanoes and forest fires |
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Carcinogenic |
Any chemical which can cause cancer in humans |
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Problems with kekule's model |
If there were c=c then addition reactions would occur but they do not. Only reacts with br2 with a halogen carrier Bond length is an intermediate between short C=C and long C-C The enthalpy change of hydrogenation is less exothermic than expected |
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Benzene structure and bonding |
-P orbital above and below the carbon plane overlap and form a high electron density PIE ring. -Hexagonal planar ring, trigonal planar round each carbon, bond angles 120. -4 electrons in carbons outer shell, 3 are bonded -6 electrons 6 carbons C6H6 |
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Delocalised |
Electrons which do not belong to a specific carbon but are shared between carbons |
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Why does benzene undergo electrophilic substitution |
To maintain its stability |
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Nitration of benzene |
Concentrated nitric acid Concentrated sulphuric acid 50 degrees Produces water Round bottom flask |
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Three uses of nitrobenzene |
Dye preperation, pharmaceuticals, pesticides. |
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Why must nitration be below 50 degrees? |
So no more than one NO2 group substitutes. |
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Electrophilic substitution steps in benzene |
-electrophilie attracted and a electron pair accepted, forming a covalent bond -benzene becomes unstable so rapidly lose its h and the electron ring reforms |
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Why is cyclohexene more reactive with br2 than benzene? |
Alkenes have localised pi electrons which can polarise br2 and have a higher electron density than benzene. Electrophiles less attracted to benzene and more energy is required to break the pi cloud. |
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Phenol and sodium hydroxide |
Water and sodium phenoxide salt |
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Phenol and sodium |
Sodium phenoxide and hydrogen gas |
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Why does phenol react with bromine at room temperature?? |
The lone pair of electrons in oxygen 's p orbital it drawn into the delocalised electron ring which created a higher electron density and activates the ring. This means bromine can be polarised. |
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Two uses of alkyl phenols |
Surfactants, detergents |
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Two uses of chlorophyll phenols |
Antiseptics, disenfectants |
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4 uses of phenols |
Epoxy resin for paints, aspirin, pharmaceuticals and dyes |
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What would you see when bromine water is added to phenol? |
Turns from Orange to colourless and a white precipitate is formed |
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When oxidising acidified potassium dichromate changes from... |
Orange to green |
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Reducing agent |
NaBH4 |
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How can you detect the precence of an aldehyde or a ketone? |
Add bradys reagent (2,4-DNP) and an orange precipitate will form. |
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Ethanoic acid and Na react together to form... |
Sodium ethonoate and hydrogen gas. |
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Propanpic acid and potassium hydroxide reacts together to form... |
Potassium propanoate and water |
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Methanoic acid and sodium carbonate reacts to form... |
Sodium methonoate, carbon dioxide and water |
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Acid anhydride and alcohol with gentle heat reacts to form... |
An ester and a carboxylic acid |
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How do you form an acid anhydride |
The removal of a water molecule from two carboxylic acid molecules |
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Acid hydrolysis conditions and reagents |
Water, aq HCL, reflux |
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Alkali hyrolysis conditions |
Reflux, aq sodium hydroxide |
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Three uses of esters |
Perfumes, solvents and flavourings |
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When an unsaturated fat has one double bond it is refered to as a... |
Mono unsaturated fat |
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Octadeca-9,12,-enoic acid written in short hand |
18:2 (9,12) |
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Glycerol and 3 fatty acids under reflux with conc. H2SO4 |
Triglyceride ester |
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Why are trans fats bad for us? |
Increase the amount of LDL'S in the blood and decrease the amount of HDL's |
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What is biodeisel |
Ethyl or methyl ester of a fatty acid |
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name this compound (CH3CH2)NH(CH3) |
N-methyly ethyl amine |
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Propyl amine and hydrochloric acid forms |
Propyl ammonium chloride |
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What do you need to prepare amines from halogenoalkanes? |
Ethanol and NH3 |
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What conditions are required to reduce nitrobenzene to phenylamine? |
Sn (tin) concentrated HCL heated under reflux |
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What is needed to form benzadizonium chloride from phenyl amine? |
HCL aq NaNO2 below 10 degress |
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How do you form an aozo dye from benzendiazonium chloride? |
NaOH, alkaline conditions, phenol |
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What are fatty acids? |
Long chain carboxylic acids |
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Curly arrow |
Movement of a pair of electrons to either make or break a bond |
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How to male tolled reagent/ ammoniacal silver nitrate |
Aq NaOH added to aq silver nitrate until a brown precipitate of silver oxide forms. Dilute aq amonia is added until precipitate just disolves. |
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What is the oxidising species in tollens reagent? |
Silver ion which gets reduced to silver metal |
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Trans isomer |
E isomer Different sides |
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Why is reflux used? |
To prevent loss of reactants and products via evaporation |
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Primary amine |
A compound containing nitrogen where the nitrogen is attached to one carbon only |