the nature of analytical chem Flashcards
a measurement science consisting of set of powerful ideas and methods that are useful in all fields of science and medicine
analytical chemistry
reveals the identity of elements and compounds in a sample
qualitative chemistry
indicates the amount of each substance in a sample (analyte)
quantitative chemistry
what are the different roles of analytical chemistry
chemistry
agricultural
medicine
physics
biology
engineering
geology
environmental science
classifying quantitative analytical methods:
the results of typical quantitative analysis are computed from 2 measurements
mass or vol of sample to be analyzed
measurement of some quantity that is proportional to the amt. of analyte in the sample
what are the nature of the final measurement of typical quantitative analytical method
gravimetric method
volumetric method
electroanalytical methods
spectroscopic methods
this analytical method is costly and the speed is slow
gravimetry
what needs to be considered in the selection process
level of accuracy period
no. of samples to be analyzed (economics)
it involves obtaining a small mass of a material whose composition accurately represents the bulk of the material being sampled.
sampling
the most difficult step in an analysis and the source of greatest error
sampling (aquire the sampling)
a material is ______ if its constituent parts can be distinguished
visually or with the aid of a microscope
heterogeneous
it is the process of determining how much of a given sample is the material by its indicated name
assay
we analyze ______ and we determine ______
samples
substances
the first step in processing the sample is often the….
preparation of a laboratory sample
a _____ is ground, mixed to ensure _____, and stored for various
lengths of time before analysis begins
solid sample
homogeneity
because any loss or gain of water changes the chemical composition of solids, it is a good idea to ____ just before starting an analysis
dry samples
in preparing laboratory sample,
If the analyte is a gas dissolved in a liquid, analyte must be kept inside a ______
second sealed container
if the analyte is a gas dissolved in a liquid, analyte must be kept inside a second sealed container. why
to prevent contamination by atmospheric gases
it improves the quality of the results and provides a measure of
their reliability
replication
species other than the analyte that affect the final measurement are called ____
interference
analytical results are incomplete without an ______
estimate of their reliability
the process of continuous measurement and control
feedback system
the cycle of measurement, comparison, and control is called a
feedback loop
