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level: Spectroscopy

Questions and Answers List

level questions: Spectroscopy

QuestionAnswer
the study of the interaction between matter and radiated energy (light)What is spectroscopy?
- Reflect - Transmit - AbsorbHow 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 waveWavelength (l)
number of waves, which pass through a given point in one secondFrequency
- The measure of the height of a wave or the depth of its trough - it determines the intensity or brightness of a waveAmplitude (A)
distance traveled by a wave in one secondVelocity (c)
the number of wavelengths per cm - equal to the inverse of a wavelength expressed in cmWave number
c = lv speed of light is 3 x 10^8 - shorter l means greater frequency and higher energyspeed of light equation
E = hv E - energy h = planks constant (6.626 x 10^-34 J/s) v = freq of radiationEnergy 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 dintensitySpectrometers
.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 intensitiesClassify 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 bondingMain Energy jumps associated with absorption of radiation
the lower the wavelength of light absorbedThe larger the energy jump...
200nm - 800nm (1.5eV - 6.2eV)What range does an absorption spectrometer work?
groups in a molecule that absorb lightChromophores
A = ecl e - M^-1cm^-1 (or mol/L/cm) c - M (or mol/L) l - cmBeer-Lambert Law
has filter/monochromator between source and sample to analyse one wavelength at a timeSingle 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 readingsDouble beam instrument