Analytical Chemistry UPDATED Exam Questions And CORRECT Answers
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Course
Analytical Chemistry
Institution
Analytical Chemistry
Analytical Chemistry branch of chemistry that deals with separation, identification, and
determination of components present in a sample. Also includes coverage of chemical
equilibrium and statistical treatment of data.
-ex.
clinical analysis: blood and urine tests
environmental: water puri...
Analytical Chemistry UPDATED Exam Questions And CORRECT Answers Analytical Chemistry ✔✔✔ branch of chemistry that deals with separation, identification, and determination of components present in a sample. Also includes coverage of chemical equilibrium and statistical treatment of data. -ex. clinical analysis: blood and urine tests environmental: water purity Forensic: DNA and fiber tests Industrial: drug and metal purity Qualitative Analysis ✔✔✔ determinin g what chemical species are present in a sample Quantitative Analysis ✔✔✔ determining how much of a chemical species is present in a sample Types of Analysis ✔✔✔ -gravimetric: methods based on measured weight -volumetric: measured volume -electrochemical: measured current, potential, or resistance -spectroscopic: measured interactions of a species with EM radiation -chromatographic: separation of material due to its interactions with 2 different phases -chemometric: statistical treatment of data Bulk Matter/Object ✔✔✔ subject of investigation Sample ✔✔✔ part of bulk matter taken Analysis/Determination ✔✔✔ -sample is analyzed -analyte=substance measured -process of measuring is determination Complete Analysis ✔✔✔ goal to determine amount of each com ponent in sample Ultimate Analysis ✔✔✔ find amount of each element present without regard to composition Partial Analysis ✔✔✔ determine one or limited number of species in sample (most common) Total Analytical Process ✔✔✔ 1.Statement of Problem 2.Definitio n of objective 3.Selection of procedure 4.Sampling 5.Sample preparation 6.Measurement and evaluation of data 7.Report and conclusions 1. Statement of the Problem ✔✔✔ ex. too much caffeine is harmful chocolate contains caffeine and theobromine (biochemical precurser) 2. Define Objective ✔✔✔ ex. determine amount of caffeine in a chocolate bar 3. Select Procedure ✔✔✔ ex. research or develop own method What is nature of sample? Elemental, Molecular, Functional group? Do we need qual. and quant.? How accurate? How much material is available? How much damage will be done to sample? 4. Sampling ✔✔✔ must obtain representative sample -homogenous vs. heterogenous 5. Sample Prep ✔✔✔ change sample to a form suitable for method being used Dry out to get accurate weight? Dissolve? Eliminate or mask interferents? Convert analyte to single form. 6. Measurement and Evaluation of Data ✔✔✔ measure a response that is proportional to concentration of analyte -gravimetric: weight of precipitate -volumetric: volume of titrant -Spec: amount of light absorbed -chromato: areas of peaks establish relationship between measured response and analyte conc. (i.e. calibration w/ standard) -replicated measurements to assess uncertainty in analysis and guard against error -use different method s to ensure same result -calculate results by applying standard curve and estimating error Standard ✔✔✔ -prepared identically to sample -have similar composition/matrix -prepared over range that is expected 7. Report and Conclusion ✔✔✔ report calculated results using standard usable format -conclusion should be consistent with data measured Chromatography ✔✔✔ based on passage of constituents to be separated between two immiscible phases -mobile phase: gas or l iquid that passes through a column -stationary phase: solid or liquid that doesn't move Eluent ✔✔✔ fluid entering the column
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