Polarimetry —This measure the change in the degree of rotation of plane-polarize
ID: 517918 • Letter: P
Question
Polarimetry—This measure the change in the degree of rotation of plane-polarized light caused by one of the components over time.
Spectrophotometry—This measure the amount of light of a particular wavelength absorbed by one component over time. (The component absorbs its complementary color)
Total pressure—The total pressure of a gas mixture is stoichiometrically related to a partial pressures of the gases in the reaction.
I'm needing these three terms put into simple explanations and scenarios for how they're used.
Explanation / Answer
Polarimetry : It is a simple non destructive technique which measures the optical activity of organic and inorganic compounds. A compound is known to be optically active if it rotates the linear plane polarised light when passing through it.
For example : Polarimetry is generally used for 1. Identification of sugars 2. Measure the reaction rate of hydrolysis of sugars.
The angle of rotation of polarized light passing through the solution is measured with a polarimeter. The reaction is C12H22O11 + H2O + H+ ----------> C16H12O6 + C6H12O6 + H +
Sucrose Glucose Fructose
Sucrose is dextrorotatory but the mixture of Glucose and Fructose is slightly laevorotatory.
By the degree of rotation the reaction rate can be monitored and different sugars also can be identified. Each sugar has its own degree of rotation.
Spectrophotometry : The basic principle in the spectrophotometry is that the how much light is absorbed or transmitted over a range of particular wavelenght by a chemical compound/ molecule.
There are different types of spectrophotometry like:
Infrared spectrophotometry
Ultra violet visible spectrophotometry
Nuclear Magnetic Resonance Spectrophotometry
Mass Spectrophotometry.
Each has its own principle and its applications in the different fields.
Total Pressure : According to Dalton "'The total pressure of a mixture of gases equals the sum of the pressures that each would exert if it were present alone"'.
For example this can applied or used in case of Deep Sea divers who use special gas mixtures in their tanks, instead of compressed air to avoid the serious conditions called 'the bends'. This law can be used to measure the totsl pressure in the cylinder at particular temperature.
The equation used is P=n(RT/V)