Fe 211 I.Midterm Summary




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.


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