Theory of Spectrophotometry Flashcards
1
Q
what does a spectrophotometer measure?
A
the amount of light absorbed/transmitted
2
Q
how do you measure absorbance with a spectrophotometer?
A
sample placed in cuvette and light of selected wavelength is passed through the sample
3
Q
how is transmittance measured?
A
It (light out)/Io (light in)
4
Q
how is absorbance (A) measured?
A
Io (light in)/ It (light out)
5
Q
what factors affect absorbance (A)?
A
- [sample] ∝ to A
- path length x [sample] ∝ A
- tendency for solution to absorb a particular wavelength (ε)
6
Q
what is beer-lambert’s law?
A
A = εCL
ε- molar absorptivity
C- concentration
L- length of light
