CHAM LAB TEST 2025
ph meter - ANSWER thin glass bulb containing 0.1M HCL in contact with
metal wire electrode.
in solution, potential established through thin glass wall
compares signal with signal in standard buffer solution
buffer effectiveness is dependent on - ANSWER pH, concentration, volume
and identity
buffer ability at varying ranges of pH - ANSWER phosphate buffer
what colour is ONP - ANSWER yellow
at 420 nm
Jablonski Diagram - ANSWER A diagram of the electronic states of a
molecule and transitions between them;
the states are vertically ordered in order of increasing energy and horizontally
grouped by spin multiplicity.
within any energy level (S) there are - ANSWER other different energy levels
as a result of different vibrational states (V1,V2)
how long does absorption take
how long is molecules excited for - ANSWER 10^ -15 seconds
, 10^-12 seconds, excited e- returns to one of the vibrational rotational states
associated with ground state
=coupled with loss of heat
source of light utilized is a function of - ANSWER wavelength instrument can
be employed at
reliability of light source intensity
wavelength output
longevousness
cost
monochromator - ANSWER to divide the light emitted by the lamp into as
many distinct various wavelengths as possible
= utilizes prisims or gratings
= more frequent grating: very uniform, accurate etching patterns
= can be wavelength selective at sub-0.1 nm
our lab spectrophotometers use mirrors and lenses to focus the light -
ANSWER
focus light into 1mm diameter, 8mm above cuvette bottom
micro-volume spectrophotometer - ANSWER compress 1-2.5uL between 2
pedestals
compressed sample forms a short column and light is delivered and det3ected
using fiber optical cable inserted into the center of both pedestals
detectors - ANSWER quantify intensity and sometimes wavelength of light
convert light to electrical signal and amplify it
to send to computer
PMT, CCD, silicon photodiodes
if absorbance is 2
how much light absorbed by analyte - ANSWER 99
ph meter - ANSWER thin glass bulb containing 0.1M HCL in contact with
metal wire electrode.
in solution, potential established through thin glass wall
compares signal with signal in standard buffer solution
buffer effectiveness is dependent on - ANSWER pH, concentration, volume
and identity
buffer ability at varying ranges of pH - ANSWER phosphate buffer
what colour is ONP - ANSWER yellow
at 420 nm
Jablonski Diagram - ANSWER A diagram of the electronic states of a
molecule and transitions between them;
the states are vertically ordered in order of increasing energy and horizontally
grouped by spin multiplicity.
within any energy level (S) there are - ANSWER other different energy levels
as a result of different vibrational states (V1,V2)
how long does absorption take
how long is molecules excited for - ANSWER 10^ -15 seconds
, 10^-12 seconds, excited e- returns to one of the vibrational rotational states
associated with ground state
=coupled with loss of heat
source of light utilized is a function of - ANSWER wavelength instrument can
be employed at
reliability of light source intensity
wavelength output
longevousness
cost
monochromator - ANSWER to divide the light emitted by the lamp into as
many distinct various wavelengths as possible
= utilizes prisims or gratings
= more frequent grating: very uniform, accurate etching patterns
= can be wavelength selective at sub-0.1 nm
our lab spectrophotometers use mirrors and lenses to focus the light -
ANSWER
focus light into 1mm diameter, 8mm above cuvette bottom
micro-volume spectrophotometer - ANSWER compress 1-2.5uL between 2
pedestals
compressed sample forms a short column and light is delivered and det3ected
using fiber optical cable inserted into the center of both pedestals
detectors - ANSWER quantify intensity and sometimes wavelength of light
convert light to electrical signal and amplify it
to send to computer
PMT, CCD, silicon photodiodes
if absorbance is 2
how much light absorbed by analyte - ANSWER 99
