Chemistry

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• catalysed by an enzyme in yeast (zymase)
• 37C
• anaerobic
• concentration of 14% alcohol by volume

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• catalyst: phosphoric acid
• high temperature: 300C
• 60 atm
• uses steam
• 95% conversion
• unreacted gases are recycled and passed through the reactor again

• Methanol: clean burning fuel, feedstock, can be converted into methanal and ethanoic acid
• Ethanol: drink, perfumes, cleaning fluids, fuel

• Water solubility: hydrogen bonds form between the polar -OH groups of alcohol and water molecules
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• Volatility and boiling points: high melting and boiling points, low volatility because of hydrogen bonds

• -OH group attached to C bonded to no or one alkyl group
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• -OH group attached to a C bonded to two alkyl groups
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• -OH group is attached to a C bonded to three alkyl groups
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• Alcohols burn completely to form carbon dioxide and water
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• Distil: form an aldehyde, catalyst is acidified potassium dichromate solution (K₂Cr₂O₇/H₂SO₄)
• Reflux: form a carboxylic acid, same catalyst
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• Solution turns from orange to green

• Heat: form a ketone, catalyst is acidified potassium dichromate (K₂Cr₂O₇/H₂SO₄)
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• resistant to oxidation
• oxdidating agents remains orange

• alcohol is warmed with a carboxylic acid
• acid catalyst: usually concentrated sulfuric acid
• an ester and water is produced
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• form an alkene
• heating under reflux
• phosphoric acid catalyst present
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• general formula: C_nH_2n+1X (X is the halogen)
• fluoro- F
• chloro- Cl
• bromo- Br
• iodo- I

• refridgerants
• aerosol propellants
• dry-cleaning solvents

• Polar: halogen atoms are more electronegative than carbon atoms, bonded electron pair is attracted more towards the halogen atom
• polarity decreases down the halogen group- electronegativity decreases
• electron-deficient carbon atom attracts nucleophiles

electron pair donor

a nucleophilic substitution reaction: a nucleophile is attracted to an electron-deficient centre or atom where it donates a pair of electrons to form a new covalent bond

• reaction with hot aqueous acid
• the halogen atom is replaced by a hydroxide ion
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• Polarity: C-F bond is the most polar amongst the halogenoalkanes, so the carbon atom should attract the nucleophile most readily and give the fastest reaction...
• But...
• Bond enthalpy is more important the polarity
• Bond enthalpy: C-I bond is the weakest so is broken more easily, so has a faster reaction . As the rate of raction increases, the bond enthalpy weakens
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heating halogenoalkane with aqueous silver nitrate with ethanol added

• Uses: drainpipes, plastic window frames, sports equipment, toys, packaging
• polymerisation of chloroethene
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• Uses: coating pans, nail polish
• polymerisation of tetrafluoroethene

• They were first developed, because refrigeration gases at the time were toxic. CFC replaced these gases as it was non-toxic and unreactive.
• CFC's remain stable until they reach the stratosphere, where hey break down in the presence of UV radiation to form chlorine radicals. These radicals catalyse the breakdown of the ozone layer

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• Yield can be moles or mass

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• Benefits of high atom economy: reduced amount of waste products
• Addition reactions: 100% atom economy, no waste products
• Substitution reactions: waste products, less efficient
• Some reactions have a high percentage yield but low atom economy

• absorption of infrared radiation causes covalent bond to vibrate (stretching or bending motion)
• breathalysers: measure ethnol levels by using infrared spectroscopy
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• Early developments: used to determine the mass-to-charge ratios of ions
• Uses: to identify unknown compounds, to determine the abundance of each isotope in an element, to gain further information abou the structure and chemical properties of molecules
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• UV radiation provides the energy to break the covalent bond
• Bonds break by homolytic fission