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64 Cards in this Set
- Front
- Back
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What's the visible spectrum of light? |
400nm - 200 nm |
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What's the relationship between Absorbance and Concentration? |
Directly proportional |
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What is the function of light energy absorbed of? |
-Concentration -Distance through a sample -Molar Abosorptivity |
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(External) Standards Curve |
- Separate preparation of analyte -known concentration -matrix matched -responds the same as analyte |
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What is the matrix of solution? |
Anything in the solution other than the analyte |
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What is an analyte? |
The solution of unknown concentration |
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How do you prepare External Standards? |
Seperatly |
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What is an Internal Standard ("spike")? |
-Part of an analytical run -Known Concentration -Matrix is identical (same-solution) -Standard responds predirectly compared to analyte |
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What is BTEX? |
-Benzene -Touene -Ethyl benzene -Xylene |
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What is the BTEX internal standard? |
tert-butyl benzene |
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What's FID stand for? |
Flame Ionization |
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What does an FID do? |
-Form Carbon Dioxide -Measure Carbon Dioxide |
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What is MoSA? |
Method of Standard Additions -Like an internal standard -Added material is the analyte itself |
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What is the aliquot? |
The precisely measured portion of a sample used to determine the quantity of an anaylte present |
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What does Vi Stand for? |
The volume of the aliquot |
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What does Vo stand for? |
The volume of the standard |
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What does VM stand for? |
Volume of the moisture |
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What does [X]M Stand for? |
The concentration of the analyte that originally came from the aliquot |
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What does [S]M stand for? |
The concentration of the analyte in the mixture of the analyte and the addition that came from the standard solution |
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What does [X] mean? |
Unknown |
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What does [S] mean? |
precisely prepared |
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What's [Ix] stand for? |
the signal of the aliquot of the analyte |
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What's [Is+x] stand fpr? |
the signal generated by the mixture of the aliquot & of the added standard solution |
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What's the slope term? |
(Ix)/[Xi] |
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What's the y-intercept term? |
[Ix] -Signal without adding a spike |
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What's the x-term? |
-The set of variables under our control [S]o*Vs/Vi |
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What's the y-term? |
-dependent signal generated (Is+x)([V]m/[V]i) |
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Variable Volume Method |
-Requires more work for x & y values to graph -Intercept is the actual value |
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Fixed Volume Method |
-Less work to determine y and x values to grap -Intercept is not the actual value |
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What's a Radical? |
Anything with an unpaired electron |
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What is a nebulizer? |
A pneumatic device which accomplished the bulk of sampling and reduction of sample volume |
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What's AA spectromtry? |
Atomic Absorption spectromtry -Quantitative technique where the sample must be converted to a suitable form |
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What's a sample for an AA like? |
-Ususally aqueous -may/not have a complex matrix may contain an element of interest my contain and element of interest where it is complexed with other materials |
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What must a sample do before reaching the flame? |
-Attaining sample through an aspiration tube -eliminate a large volume |
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What is the fire required to do in Flame AA? |
-Ensure solvent is removed -Dissociate materials -Vaporize Materials -Convert inorganic analytes (usually metals) to free atoms/ radicals |
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What's the burner do in Flame AA? |
Prevents turbulence Reduces 'flame noise' |
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What's the largest usable droplet in flame AA? |
20 micro metres |
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What's the first step of Flame AA? |
Solvent gets evaporated into minuute dry particles |
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What's the second step of Flame AA? |
Dry particles get vaporized |
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What's the third step of Flame AA? |
Some of the particles get progressively dissociated |
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What's step four of Flame AA? |
A portion of the neutral atoms/radicals become thermally excited or ionized (Collision dependent) (are a hinderence in AA, and in FES they are desired) |
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How much of the sample has a chance of getting to the flame in AA? |
10% |
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What's the max amount of acid a neubulizer can take? |
0.5% |
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What's step 5 in flame AA? |
Neutral Atoms or radicals may combine with other neutral atoms/radicals in the flame gas to make new compunds |
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What tolerance does the AA Spec have? |
0.001 nm tolerance |
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What do you need to get valid results from an AA Spec? |
A Narrow bandwidth |
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What's the medium in an AA Spec? |
Flame Gas |
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What are unexcited atoms capable of doing? |
Absorbing radiation |
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What's causes the band broadening effect in AA Spec? |
Doppler effect Lorentz |
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What does the Doppler effect cause an AA Spec? |
Flame causes atomic movement |
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What does the Lorentz effect cause an AA Spec? |
Collisions of a gas and an analyte |
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What's and HCL (hallow cathode lamp) |
a pyex lamp with a quartz window end |
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How many main causes are there for interferance in AA? |
Four main causes |
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Name four of the interferences in AA |
Emission Spectral Interference Vaporization Interference Ionization effects |
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What causes Background Absorbance in AA? (Emission) |
-Light scattering particles in a flame -Alkyl halides |
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What is spectral interference in a sample for AA? |
A line of interest that cannot be resolved from lines of other elements in a sample |
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What causes vaporization interference in AA? |
Chemical interactions between analytes, solutions, and gases. |
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What causes ionization effects in AA? |
Nitrous Heat ionizing atoms |
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What is Accuracy? |
How close it is to the true value |
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What is precision? |
How close the results are together |
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What does chemical instrumentation involve? |
-Automating repetitive processes -Ensuring consistent quantities are used -Detecting smaller quantities of material |
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What does chemical instrumentation do? |
Improve the ability to analyze samples |
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What type of answers does qualitative analysis' give? |
yes/no answers |
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What type of answers do quantitative analysis' give? |
How much is present |
