Chapter 12 - Analysis of Organic Compounds by Spectroscopic Techniques

Question 1

Electromagnetic waves

Answer 1

produced by electrically charged particles moving

Question 2

electromagnetic spectrum

Answer 2

the range of electromagnetic radiation

Question 3

spectroscopy

Answer 3

use of absorption, emission or scattering of electromagnetic radiation by matter to qualitatively or quantitatively study the matter

Question 4

spectroscopy: absorption

Answer 4

transition from a lower level to a higher levels

Question 5

spectroscopy: emission

Answer 5

transition from higher level to lower level with transfer of energy from emitter to radiation field

Question 6

spectroscopy: scattering

Answer 6

redirection of light due to its interaction with matter

Question 7

emission spectrum

Answer 7

coloured lines correspond to the emitted energies

Question 8

absorption spectrum

Answer 8

black lines correspond to the energies absorbed

Question 9

inferred spectroscopy

Answer 9

analytical technique that uses infrared part of electromagnetic spectrum to investigate vibrational energy of molecular bonds

Question 10

percentage transmittance

Answer 10

amount of particular frequency that passes through compound

Question 11

what percentage transmittance means all wavelength passed through

Answer 11

100

Question 12

equation of wave number

Answer 12

1 / wave length

Question 13

finger print region

Answer 13

part of IR spectrum below 1400cm-1 that is used to identify functional groups

Question 14

nuclear magnetic resonance (NMR) spectroscopy

Answer 14

technique used to determine an organic compounds structure

Question 15

alpha-spin state

Answer 15

protons that align with the external magnetic field.

in a lower energy state

Question 16

beta-spin state

Answer 16

protons that align against the external magnetic field.

in a higher energy state

Question 17

proton NMR spectroscopy

Answer 17

used to determine the chemical environment of hydrogen atoms in compounds and gives information about the environments neighbouring each hydrogen atom

Question 18

hydrogen atoms attached to the same carbon atom are said to be what?

Answer 18

equivalent

Question 19

peak area in low resolution 1H NMR is proportional to what?

Answer 19

the number of hydrogen atoms in the environment

Question 20

splitting patterns in high resolution NMR follow the n+1 rule where n is equal to what?

Answer 20

the number of equivalent protons on the neighbouring carbon

Question 21

carbon-13 NMR spectroscopy

Answer 21

used to determine the chemical environment of carbon atoms in compounds

Question 22

resonance

Answer 22

a signal in the spectrum

Question 23

TMS (tetramethylsilane)

Answer 23

reference molecule added to the sample to account for different machines and conditions.
chemically unreactive and easily removed from sample

Question 24

shielding effect

Answer 24

attraction between an electron and nucleus in any atom with more than one electron shell

Question 25

mass spectroscopy

Answer 25

used mass-to-charge, m/z, ratio of atoms, molecules ad fragments of molecules to identify substances

Question 26

mass spec ionisation

Answer 26

beam of electrons knocks off electrons off the sample forming positive ions

Question 27

mass spec acceleration

Answer 27

positive ions accelerated by an electric field

Question 28

mass spec deflection

Answer 28

as positive ions enter magnetic field they’re deflected from their pathway according to a m/z

Question 29

parent molecular ion

Answer 29

ion produced after one electron is knocked off by an electron

Question 30

free radical

Answer 30

atom or group of atoms that has at least one unpaired electron and is therefore unstable and highly reactive

Question 31

base peak

Answer 31

tallest line in the spectrum.

height of 100