Study Set Content:
A quantitative, non-destructive measuring technique based on optical principles that are evident in nature
REFRACTOMETRY
~ A method of measuring substances refractive index and assess their compostion or purity.
REFRACTOMETRY
REFRACTOMETRY ~ A technique that measures how light is() when it passes through a given substance.
refracted
Defined as the ratio of the speed of light in a vacuum to the speed of light in another substance.
REFRACTIVE INDEX (N)
Simply, the amount by which light is refracted.
REFRACTIVE INDEX (N)
It is a quantity which is a () for a pure substance under standard conditions of temperature and pressure.
constant
REFRACTIVE INDEX (N)depends of the
temperature and the wavelength of the light.
˗ Help () the identity of a sample by comparing its refractive index to known values.
identify or confirm
Assess the purity of a sample by comparing its refractive index to the value for the
pure substances.
˗ Determine the concentration of a solute in a solution by comparing the solution’s refractive index to a
standard curve
Temperature: due to accompanying change in density. It is () to the RI.
inversely proportional
refractive index of a transparent medium gradually () with increasing wavelength;
decreases
refractive index of a transparent medium gradually decreases with increasing wavelength; this effect is referred to as
normal dispersion.
is the appropriate wavelength for the determination of the RI
sodium D-line at 595 nm
refractive index of a substance() with pressure because of the accompanying rise in density.
increases
Viscosity: it is () to the RI
inversely proportional
FACTORS AFFECTING REFRACTIVE INDEX
Temperature
Wavelength
Pressure
Viscosity
The main principle involved in refractometry is the refraction based on the () that passes in the different mediums
speed of the light
Light enters into the light denser medium to high denser medium at an angle, that is, with
bent
Light enters into the light denser medium to high denser medium at an angle, that is, with bent. The bent in the light ray is known as the
refraction
