Instrumental Analysis Fundamentals Of Spectrophotometry

Question 1

What is Spectroscopy?

Answer 1

Basta kahit anong procedure na na gumagamit ng EMR na may matter to IDENTIFY and/or ESTIMATE an analyte.

Question 2

What does it mean when you said you IDENTIFY an analyte?

Answer 2

It pertains to Qualitative Analysis (the quality)

Question 3

What does it mean when you said you ESTIMATE an analyte?

Answer 3

It pertains to Quantitative Analysis (numbers, etc)

Question 4

What is EMR?
(2 answers)

Answer 4

1. It is describes as both PARTICLES and WAVES (the dual nature of light)
2. waves consist of perpendicular and oscillating electric and magnetic fields

Question 5

EMR is also?

Answer 5

Light

Question 6

Light waves can be characterized By:

Answer 6

1. Wavelength
2. Frequency.
3. Wave Number

Question 7

What can the wave nature of light explain?

Answer 7

can explain phenomena such as reflection, refraction and diffraction.

Question 8

Wavelength (, Greek lambda)

Answer 8

Distance from one wave peak
to the next.

Question 9

Number of peaks that pass a
given point per second.
Units: Cycles/second or s-1 or Hertz (Hz)

Answer 9

Frequency (, Greek nu

Question 10

Wavenumber

Answer 10

Number of waves per cm.

Question 11

Electromagnetic radiation consists

Answer 11

discrete packets of energy, which we call photons

Question 12

the quanta of light.

Answer 12

Photons

Question 13

Each photon carries the energy
What is the unit for energy?

Answer 13

Joule

Question 14

What is Planck’s constant?

Answer 14

6.626x10^-34J.s

Question 15

The _____ the energy, the_____ the frequency and wavenumber and the _____ the wavelength

Answer 15

Greater
Higher
Shorter

Question 16

What can the PARTICLE nature of life explain?

Answer 16

can explain phenomena like absorption and emission of light.

Question 17

Regions of electromagnetic radiation:

Question 18

ABSORPTION OF LIGHT:
Microwave energy causes:

Answer 18

ROTATION of compounds

Question 19

ABSORPTION OF LIGHT:
IR energy causes:

Answer 19

Promotes BOND STRETCHING

Question 20

ABSORPTION OF LIGHT:
UV/VIS energy causes:

Answer 20

promotes ELECTRONS into HIGHER orbitals

Question 21

ABSORPTION OF LIGHT:
Short Wavelength of UV and X-rays causes:

Answer 21

can ionize molecules or even break bonds.

Question 22

Most excited molecules relax again to the ground state emitting 7 the excess energy in the

Answer 22

form of heat

Question 23

What happens when a molecule absorbs UV-Visible radiations

Answer 23

1. When a molecule absorbs light having sufficient energy (e.g. UV-Vis radiation) to cause an electronic transitions, additional vibration and rotation transitions also occur
2. Molecule can absorb one photon of just the right energy to cause the following simultaneous changes:
   2.a AtransitionfromthegroundelectronicstateE0totheE1excited electronic state
   2.b Achangeinthevibrationalenergyfromthegroundvibrationalstate of E0 to an excited vibrational state of E1
   2.c AtransitionfromonerotationalstateofE0toadifferentrotational state of E1
   TO BE CONTINUED.. PAGE 9

Question 24

What is spectrum?

Answer 24

Spectrum (a graph that shows how absorbance varies with wavelength)