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level: Spectroscopy

Questions and Answers List

level questions: Spectroscopy

Question	Answer
the study of the interaction between matter and radiated energy (light)	What is spectroscopy?
- Reflect - Transmit - Absorb	How does matter interact with electromagnetic radiation?
the distance (measured in the direction of propagation) between two points in the same phase in consecutive cycles of a wave	Wavelength (l)
number of waves, which pass through a given point in one second	Frequency
- The measure of the height of a wave or the depth of its trough - it determines the intensity or brightness of a wave	Amplitude (A)
distance traveled by a wave in one second	Velocity (c)
the number of wavelengths per cm - equal to the inverse of a wavelength expressed in cm	Wave number
c = lv speed of light is 3 x 10^8 - shorter l means greater frequency and higher energy	speed of light equation
E = hv E - energy h = planks constant (6.626 x 10^-34 J/s) v = freq of radiation	Energy equation
- instruments that measure the properties of light in a specific region of the electromagnetic spectrum, determining light intensity - utilise single beam of light to produce spectral lines to determine wavelength an dintensity	Spectrometers
.	Typical Spectormeter
a spectrometer which measures intensity as a function of wavelength (or colour) of light (absolute intensity of light).	Spectrophotometer
- Wavelength they analyse - Methods of measurement - Means of data acquisition - Ability to differentiate between intensities	Classify Spectrophotometers
- Absorption (UV/Vis, infrared) - Emission (Fluorescence) - Scattering (Raman)	Spectroscopic Techniques
1 - pi bonding to pi anti bonding 2 - non bonding to pi anti bonding 3 - non bonding to sigma anti bonding	Main Energy jumps associated with absorption of radiation
the lower the wavelength of light absorbed	The larger the energy jump...
200nm - 800nm (1.5eV - 6.2eV)	What range does an absorption spectrometer work?
groups in a molecule that absorb light	Chromophores
A = ecl e - M^-1cm^-1 (or mol/L/cm) c - M (or mol/L) l - cm	Beer-Lambert Law
has filter/monochromator between source and sample to analyse one wavelength at a time	Single beam instrument
- contains a splitter and a series of mirrors to get the beam to the reference sample and the sample to be analysed - allows for more accurate readings	Double beam instrument