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Absorption of light (UV-VIS spectroscopy)

Product No: P3070101

Principle

The structures of molecules are not changed by their chemical environment in the gas phase. In contrast to this, on transition to the condensed phase, in dilute solution, the solvent changes the binding state of the dissolved substance. One of the way this influence makes itself shown is in the elctron spectrum (solvatochromatic shift).

Tasks

Plot and discuss UV-visible absorption spectra of methyl orange in various solvents.
From the decadic molar extinction coefficients of the bands in the visible range, determine the type of electron transition that causes these bands.
Plot the wavelengths of the absorption maxima in the visible range against the dielectric constants of the various solvents.

What you can learn about

Absorption of light
Electron excitation
Influence of solvents
Solvatochromic, hypsochromic and bathochromic shifts
Lambert-Beer's Law
Decadic molar extinction coefficient

Materiallist (Excerpt)	Product	Amount
Spectrophotometer 190-1100 nm	35655-93	1
Set of Precision Balance Sartorius CPA 623S and measure software, 230 V	49224-88	1
Cells f.spectrophotom., quartz, 2	35665-02	1
Micro-l syringe, 100 micro-l	02606-00	1
N,N-Dimethylformamide, puriss., 1 l	31259-70	1
Ethyl alcohol, absolute 500 ml	30008-50	1
Methyl orange soln., 0.1% 250 ml	31573-25	1
Water, distilled 5 l	31246-81	1
Ethylene glycol 250 ml	30085-25	1
Pipette dish	36589-00	1
Methanol 500 ml	30142-50	1
Pipettor	36592-00	1
Weighing dishes, square shape, 84 x 84 x 24 mm, 25 pcs.	45019-25	1
Volumetric flask 100 ml, IGJ12/21	36548-00	1
Microspoon, steel	33393-00	1
Funnel, glass, top dia. 55 mm	34457-00	1
Wash bottle, plastic, 500 ml	33931-00	1
Volumetric pipette, 1 ml	36575-00	5
Laboratory Experiments Physics, Chemistry, Biology andApplied Sciences, CD-ROM, incl. operating manuals	16502-42	1