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1 Exakte Antworten 23 Text Antworten 0 Multiple Choice Antworten
Fenster schliessen

Define: analyte (1p)

analyte(s): compound(s) of interest in an analytical procedure
Fenster schliessen

Define "analytical chemistry" and the two common categories of it (3p)

Analytical chemistry: measurement of propertie of a substance or system such that information about the chemical make-up of that system is obtained

1. Qualitative analysis: analysis by physical properties without quantitative data (some or all of the constituents of the system in question are identified)
2. Quantitative analysis: the concentration (or mass) of some or all constituents in a system are measured and identified

Fenster schliessen

What are some factors to method selection? (5p)

1. Elemental or molecular in form
2. Organic or inorganic
3. Volatile or non-volatile
4. Low, medium, or high molecular weight
5. Ionic or non-ionic

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What are the two most important considerations for method selection? Define them. (2p)

1. Selectivity: ability of the method to discriminate between different atoms/ions/compounds
2. Sensitivity: magnitude of the change in signal that results from an incremental change in concentration

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Definte: limit of detection (LOD) (1p)

Limit of detection (LOD): lowest comcentration of a compound that may be statistically differentiated from the background noise

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What two ways can you increase sensitivity? (2p)

1. Improve equipment used
2. Reduce the background noise

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What are "descriptors" and what is the minimum number of them necessary to make a clear judgement? (2p)

Descriptors: element or term, qualities, that ha s the function of describing or identifying someone or something in particular

At least 2, completely independent descriptors are required to recognize someone from a distance

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What does it mean when a presumptive colour test indicates that the object is positive for a certain substance? (1p)

The object is presumed to be positive for the substance, and fails to be excluded from the evidence