Atomic Absorption Spectroscopy Flashcards
(12 cards)
1
Q
Systematic error
A
- consistently higher or lower than actual value
- flaws in method/instrument or human error
2
Q
How to fix systematic error
A
use the correct technique and properly calibrated instruments
3
Q
Reliability
A
a measure of how an experiment can be repeated with consistent results
- affected by random error
4
Q
Precision
A
how close data values are
- affected by random error
5
Q
Random error
A
- inconsistently higher or lower than actual value
6
Q
Random error fix
A
more trials to get a clearer average
7
Q
Systematic error example
A
- measuring meniscus consistently wrong
- weight isn’t calibrated properly
8
Q
Random error example
A
- qualitative observations (differences in human observations)
- reading from ruler or thermometer isn’t exactly precise
9
Q
Atomic Absorption Spectroscopy
A
identifies amount of element present by measuring absorbed light
QUANTITATIVE
10
Q
AAS Process
A
- sample goes through hollow cathode lamp (made of same elements so emitted light will be same wavelengths for elements to absorb)
- sample is sprayed onto burner -> makes it into a gas (atomiser)
- light is passed through sample, then goes through slit
- defraction grating monochromoter - light defracts through prism or light filter -> filters out other wavelengths
- Detector - measures intensity of light
- Output display spectra - gives absorbance spectra (like an inverted emission spectrum)
11
Q
Accuracy
A
how close the data values are to true value
- affected by systematic error
12
Q
Validity
A
the accuracy of a measurement - the degree to which an instrument, statistical technique or a test measures what it’s supposed to measure
