Worksheetsاختبار التحليل الآلي
Total questions: 20
Worksheet time: 10mins
Analytical chemistry is mainly concerned with:
Synthesis of compounds
Separation and identification of substances
Industrial production
Reaction mechanisms
Qualitative analysis answers the question:
How much is present?
How fast is the reaction?
What is present?
Why does it react?
Quantitative analysis determines:
Identity of analyte
Structure of analyte
Amount of analyte
Color of analyte
The analyte is defined as:
The solvent
The matrix
The substance being measured
The reagent
The matrix refers to:
Pure analyte
All components except analyte
Instrument detector
Calibration standard
Accuracy expresses how close a result is to:
Each other
True value
Mean value
Zero
Precision describes:
Closeness to true value
Instrument sensitivity
Reproducibility of results
Systematic error
A systematic error:
Is random
Can be corrected
Changes sign randomly
Comes from reading uncertainty
Random error mainly affects:
Accuracy
Precision
Calibration
Sensitivity
Sensitivity of a method is:
Ability to detect impurities
Change in signal per unit concentration
Lowest detectable concentration
Precision of measurement
Limit of detection (LOD) is:
Lowest measurable signal
Lowest concentration reliably detected
Maximum concentration
Instrument noise
Calibration curve plots:
Signal vs time
Concentration vs signal
Signal vs concentration
Absorbance vs wavelength
Beer–Lambert law relates absorbance to:
Temperature
Path length and concentration
Pressure
Refractive index
In spectrophotometry, absorbance is measured using:
Ammeter
Voltmeter
Spectrophotometer
pH meter
Increasing path length will cause absorbance to:
Decrease
Stay constant
Increase
Become zero
A blank solution is used to:
Increase sensitivity
Remove matrix effects
Calibrate detector
Increase noise
Selectivity refers to the ability to:
Measure very small amounts
Distinguish analyte from interferents
Improve precision
Increase signal
An interference is a species that:
Improves accuracy
Enhances signal
Causes error in measurement
Acts as solvent
Instrumental methods are preferred because they are:
Slower
Less sensitive
More accurate and precise
Cheaper always
Validation of an analytical method ensures:
Instrument is new
Results are reliable
Analysis is qualitative
Sample is pure
