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OCR A-Level Chemistry Salters B > Colour by Design > Flashcards

Flashcards in Colour by Design Deck (7)
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1

What is a conjugated system

A conjugated system has alternating single and double bonds, allowing the overlap of p-orbitals

2

Colourless and coloured objects

Colourless objects reflect all visible light and do not absorb any

Coloured objects absorb the wavelength of the colour they appear

3

What are complimentary colours

Two colours which combined together produce white light

4

Factors affecting colour

-The more electrons that are delocalised in the conjugated system, the smaller the energy gap
-Smaller energy gaps result in the absorption of longer wavelengths of light absorbed

It usually takes 5 pi bonds in a conjugated system for the system to start absorbing visible light

5

The geometry of benzene

-The benzene ring is a regular, planar hexagon
-All the bond angles are 120 degrees
-All the carbon-carbon bonds are the same length

6

Stability of delocalised structures

The more delocalised a system is, the more stable it is

7

Benzene reaction with bromine

Electrophilic substitution with an iron catalyst to form bromobenzene and HBr