Chemistry, Third edition

Light and Spectroscopy Objectives Looks at the absorption and emission of light Explains how spectrometers work Discusses the ...

ELECTROMAGNETIC SPECTRUM per second.) The relationship between the wavelength, frequency and the velocity of light in a vacuum i ...

20 · LIGHT AND SPECTROSCOPY Energy transitions The quantum theory restricts the energy of a molecule or atom to certain definite ...

ENERGY LEVELS OF ATOMS AND MOLECULES Energy levels of atoms and molecules We now look at the types of energy possessed by molecu ...

20 · LIGHT AND SPECTROSCOPY mole of absorbing molecules. As a consequence of infrared absorption, the atoms in the molecule move ...

ABSORBANCE AND TRANSMITTANCE OF A SAMPLE The range and intensity of wavelengths emitted by the light source (its emission spectr ...

372 20 · LIGHT AND SPECTROSCOPY Fig. 20.6Absorbance spectra for the case shown in Fig. 20.5. (a) The absorption spectrum of the ...

MORE ABOUT ULTRAVIOLET AND VISIBLE SPECTRA Use of spectra Spectra are useful for two reasons: 1.They may be used as a ‘fingerpri ...

20 · LIGHT AND SPECTROSCOPY Experimentally, the emission spectrum of the hydrogen atom is obtained by pass- ing an electric spar ...

MORE ABOUT ULTRAVIOLET AND VISIBLE SPECTRA Key facts about the Lyman series ●As with all spectra, the greater the energy gap inv ...

20 · LIGHT AND SPECTROSCOPY Electronic spectra of other atoms The emission spectrum of sodium atoms is produced by passing an el ...

ABSORPTION SPECTRA AND COLOUR purple glow. The emission stops as soon as the light is turned off. Other common fluorescent molec ...

20 · LIGHT AND SPECTROSCOPY Colour cheese The ‘colour cheese’ summarizes the relationship between the wavelength of light most s ...

INFRARED SPECTROSCOPY Optical brighteners Fluorescent molecules known as optical brightenersare used in washing powders to make ...

20 · LIGHT AND SPECTROSCOPY If a watch glass of volatile solvent (e.g. ethoxyethane or methanol) is placed below the path of the ...

INFRARED SPECTROSCOPY light, it increases its vibrational energy from the ground vibrational energy level to the second vibratio ...

20 · LIGHT AND SPECTROSCOPY that only a few atoms in the molecule vibrate appreciably (i.e. suffer largecompres- sions, extensio ...

INFRARED SPECTROSCOPY 383 Fig. 20.19Infrared spectrum of ethyl ethanoate CH 3 CO 2 C 2 H 5. Fig. 20.20Infrared spectrum of ethan ...

20 · LIGHT AND SPECTROSCOPY irrespective of the molecule in which they are found. Typical of such groups are C=O, C–H, –NH 2 and ...

INFRARED SPECTROSCOPY 20.23). The –OH bond in carboxylic acids, also very broad, is found between 3500 and 2400 cm–1(see ethanoi ...