Spectroscopy

Question 1

final peak on a mass spectroscopy

Answer 1

molecular ion peak

Question 2

4 stages of mass spectroscopy

Answer 2

ionization
acceleration
deflection
detection

Question 3

how is relative molecular mass found from mass spec

Answer 3

molecular ion peak

Question 4

how is relative atomic mass found from mass spectroscopy

Answer 4

isotopic abundance

Question 5

ionization equation of M

Answer 5

M_(g) + e^- > M^{+<strong>.</strong>}_(g) + 2e^-

Question 6

fragmentation equation of M to P and Q

Answer 6

M^{+<strong>.</strong>} > P⁺ + Q^{<strong>.</strong>}

Question 7

why is CHCl₃ not used as a solvent for proton nmr

Answer 7

contains ¹H atoms (protons)

Question 8

proton nmr splitting

Answer 8

number of protons on adjacent atom + 1

Question 9

what does chemical shift show

Answer 9

how exposed the nucleus is

Question 10

area under peak in nmr

Answer 10

number of C’s or H’s in that environment

Question 11

standard used in ¹H or ¹³C nmr

Answer 11

tetramethylsilane TMS
Si(CH₃)₄

Question 12

why is TMS used as a standard for nmr (4)

Answer 12

all C’s and H’s are equivalent
C nd H nuclei are highly shielded as Si has low electronegativity
cheap
non-toxic

Question 14

number of peaks in ¹³C nmr

Answer 14

number of different C environments