Flashcards
Colour by Design
Cards in this deck (37)
- 1Electromagnetic Spectrum (lowest freq- highest freq)Radiowaves, Microwaves, Infrared, Visible Light, Ultraviolet, X-Ray, Gamma
- 2Complementary colours: Red- Orange- Yellow- Green- Blue- Violet-Green
Blue
Violet
Red
Orange
Yellow - 3Properties and uses of a dye:Soluble
Used to colour fabric/ clothing
Incorporated into bulk materials
Hydrogen bond to material
Id-Id bond
Acid dyes bond to proteins via ionic bonds with charged R groups - 4Properties and uses of a pigment:Insoluble
Used to cover surfaces eg. paintings - 5Ligand-A molecule with at least 1 lone pair of electrons that surrounds a central positive metal ion (to form a complex).
- 6Conjugated system:Alternating C=C and C-C bonds that form a chromophore.
- 7Delocalised electron system-Electrons are delocalised/ spread out around the entire molecule/ atom.
- 8Chromophore-An extended delocalised electron system that gives a molecule a colour.
- 9Strength of bond: C=C C-C C=C-C=CWeaker than C-C as electrons are more spread out, require less energy to excite.
Strong and require a lot of energy to break.
Require less energy to break as electrons are part of a delocalised electron system and are therefore more spread out. - 10What type of spectrum is used to identify the colour of a pigment? Why?Reflectance spectrum shows what frequency/ colour of visible light is emitted = colour of pigment.
Cannot use an absorption spectrum as pigments are insoluble and this spectrum is done for molecules in solution. - 11Emulsion-A mixture of 2 liquids that do not dissolve in one another (eg. oil and water)
- 12Porphyrins?...
- 13Mordant-A way of attaching a dye to a fabric by forming a complex that links them together
- 14Triesters:Glycerol and 3x carboxylic ('fatty') acids
- 15Hydrolysis (saponification) of triesters Reactants & products+3NAOH
-> Glycerol and Na+Carboxylate - 16Apart from alternating double/single carbon bonds, what other bonds can form/ be involved in a conjugated system?N=N
Benzene Ring - 17Why do benzene rings not react with bromine water like an alkene would?Benzene rings don't contain strict C=C bonds. The electrons are delocalised around the molecule/ring so the bromine cannot act as a nucleophile.
- 18Arenes are more stable than alkenes because...It contains a delocalised electron structure/ network which has a lower excitation energy than C=C bonds. Therefore it is more stable.
- 19Arenes often under-go ... reactions rather than ... reactions because this allows the arene to keep its ... which makes it more ...Substitution
Addition
Delocalised electron network/ structure
Stable - 20Electrophiles:Positively charged ion or molecule with a partial positive charge localised on one of the atoms that will be attracted to a negatively charged region. They react by accepting a pair of electrons to form a covalent bond.
- 21Nitration reaction reagents and conditions Benzene -> NitrobenzeneConcentrated nitric acid mixed with concentrated sulphuric acid.
Temp below 55oC
Electrophile: NO2+ produced by the reaction (O=N=O) - 22Sulfonation: Benzene -> Benzenesulfonic acidConcentrated sulphuric acid
Heated under reflux for several hours.
Electrophile: SO3 (present in conc acid) - 23Chlorination: Benzene -> chlorobenzeneAnhydrous aluminium chloride. Room temperature.
Electrophile: Cl+ - 24Bromination: Benzene-> BromobenzeneAnhydrous Iron(III) Bromide/ Iron filings.
Room temp
Electrophile: Br+ - 25Alkylation: Benzene -> ethylbenzeneAnhydrous aluminium chloride
Heat under reflux - 26Acylation: Benzene -> phenylethanoneAnhydrous aluminium chloride
Heat under reflux - 27Which two reactions are known as the friedel-crafts reactions?Alkylation and acylation
- 28Why are Friedel-craft reactions useful in organic synthesis?They add carbon side chains to benzene rings which allows them to be modified further.
- 29Why are friedel-craft reactions which form solvent-catalyst systems good for green chemistry?Reduce solvent emissions, reduce flammability, often recycle easily (less waste), reaction can be carried out at lower temp to reduce energy consumption.
- 30What are azo dyes made from?Reacting a 'coupling agent' with a diazonium ion.
- 31Diazonium formula:R-N+...N
(... = triple bond_ - 32Diazotisation reagents, conditions and recatants etc.Phenylamine + Nitrous acid -> benzenediazonium ion + 2water
under 5oC
Dilute HCl and Sodium Nitrate(III) - 33Examples of coupling agents x2:Phenols and Aromatic amines
(both have electron rich rings) - 34What bond forms in a coupling reaction?-N=N-
- 35What type of compound is formed in a coupling reaction?An azo compound (dye)
- 36Adding NH2 or SO3-Na+ groups on to an azo dye enhances:NH2- the colour of the dye
SO3-Na+- its solubility in water and its bonding to protein fibres. - 374x bonds that can be present in a chromophore:C=C
C=O
N=N
Benzene ring
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- A-Level Chemistry (F335) Flashcards on Colour by Design, created by becky.evans1511 on 12/04/2016.
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- becky.evans1511 · Apr 2016
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- Jun 20, 2016
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