ELABS Flashcards
How to calculate equivalents
equivalent weight = molecular mass / number of h+ ions per mole
how to calculate millimoles?
use 1 mole = 1000 millimoles
how to calculate mass of a compound
mass = mr x moles
how to calculate the volume of a compound
mass = density x volume
how to calculate percentage yield
Theoretical/ actual * 100
how to calculate percentage yield
percent yield = actual yield / theoretical yield x 100%
explain the process of chromatography
It is defined as the process of separation of the individual components of a mixture based on their relative affinities towards stationary and mobile phases
Principle:
The samples are subjected to flow by mobile liquid onto or through the stable stationary phase. The sample components are separated into fractions based on their relative affinity towards the two phases during their travel.
The fraction with greater affinity to stationary layer travels slower and shorter distance while that with less affinity travels faster and longer.
Explain extraction
Extraction is the process of selectively removing a compound of interest from a mixture using a solvent. For an extraction to be successful the compound must be more soluble in the solvent than in the mixture. Additionally, the solvent and mixture must be immiscible
explain crystallisation
Crystallisation is the process of separating solid compounds from the solution in the form of crystals.
This method is mainly employed for the separation of a solid in pure form from the solution.
It is a physical change.
Process of crystallisation:
Firstly the solution is heated and the solvent molecules start to evaporate.
As the solution begins to cool down the pure substance starts to form crystals, which gets collected at the surface of the solution.
The crystals are then collected and dried.
what are the methods of ascertaining purity?
Some of the analytical purity testing methods include titration, infrared spectroscopy, paper chromatography, and optical rotation.
Physical testing methods are testing its melting and boiling points.
what are the methods of ascertaining purity?
usual methods
