Lab 1 Flashcards
Visible Spectrum
400-750 nm
Colour of light:
<400 nm
Ultraviolet
Colour of light:
400 nm
Violet
Colour of light:
500 nm
Green
Colour of light:
600 nm
Yellow
Colour of light:
700 nm
Red
What colour would the object appear if it absorbed light of the following colour:
1. Ultraviolet
2. Violet
3. Green
4. Yellow
5. Red
- Colourless
- Yellow
- Red
- Violet
- Green
What are colors in compounds due to?
Chromophores
* Greek chroma (color) and phoros (bearer)
Chromophores
A region of a molecule where the energy difference between two different molecular orbitals falls within the range of the visible spectrum
Chromophore regions of organic molecules usually contain functional groups that possess some…
Unsaturation
What happens to light hitting a chromophore?
Absorbs energy
* Excites electron from ground state to excited state
True or False:
Chromophore groups can impart colour on their own
False, they can only absorb ultraviolet region on their own
* They need to be a part of a conjugate system to absorb visible spectrum
In general, what decreases as conjugation increases?
Gap between:
Highest-energy filled orbital
and
Lowest-energy vacant orbital
Wavelength of maximum absorption ——— with increasing conjugation
Increases
What are amino, hydroxy, or alkoxy groups that increase the wavelength at which light is absorbed/intensify the abosorption known as?
Auxochrome
What are characteristics of auxochromes?
Have lone pair of electrons (can extend the conjugated system by resonance)
