FE 211 – I. MIDTERM
DEFINITION OF SOME TERMS:
Analytical Chemistry: involves separating , identifying and determining the relative amounts of the components making up a sample of matter.
Qualitative Analysis: which deals with the problem of what is in a substance
Quantitative Analysis: which handles the problem of how much of each constituent is present.
Central Value: The most commoncentral value used by the chemist is the MEAN.
Precision: is a measure of how close the experimental values are to each other , or term precision is used to describe the reproducibility of results.
Accuracy: is a measure of how close the the experimental results are to the accepted values and is expressed is term of error.
Gravimetric Factor: Stoichiometric relationship between the analyte and the product weighed.This constant is sometimes called the gravimetric factor.
Colloiadal Suspensions: whose tiny particles are invisible to the naked eye .
Crystalline Suspensions: The temporary dispersion of such particles in the liquid phase is called a crystalline suspension.
Density: of a substance measures its mass per unit volume.
Specific Gravity: of a substance is the ratio of its mass to the mass of an equal volume of water at
Volumetric or Titrimetric Method: A quantitative analysis based upon the measurement of volume is called a Volumetric or Titrimetric Method.
Titration: is a reaction carried out by the carefully controlled addition of one solution to another.
Titrant or Standard solution: is a reagent of known concentration that is used to carry out a volumetric analysis.
Titrand or Sample solution: which is often placed in an Erlenmeyer flask.
Equivalence Point: in a titration is reached when the amount of added titrant is chemically equivalent to the amount of analyte in the sample.
Back Titration: It is sometimes necessary to add an excess of the Standard titrant and than determine the excess amount of by back-titration with second Standard titrant.
End point: The point at which a physical change is observed at the sample is called the end point.
Titration error: The difference in volume between the equivalence point and end point is the titration error.
Indicator: A common method of detecting end points involves the introduction of a substance called an indicator.
Primary Standards: Every volumetric method is based upon a primary standard ,which is used directly or indirectly to establish the concentration of the standard solution.
Standard Solutions: Standard solutions play a central role in all volumetric methods of analysis.