the mass spectrometer

Question 1

what can the mass spectrometer can be used to determine?

Answer 1

• all the isotopes present in a sample of an element
• identify elements

Question 2

what is on the y axis and x axis of a mass spectra

Answer 2

y axis: relative/% abundance
x axis: m/z (mass/charge ratio)

Question 3

what does the charge ratio mean on the mass spectra?

Answer 3

the charge of the ion (most likely +1, if it’s half the largest, it’s +2)

Question 4

equation for relative atomic mass

Answer 4

R.A.M = Σ (isotopic mass x % abundance)/100

Question 5

equation for relative atomic mass if relative abundance is used instead of % abundance

Answer 5

Σ (isotopic mass x relative abundance)/total relative abundance

Question 6

what are the two isotopes of Cl₂?

Answer 6

Cl-35 (75%) and Cl-37 (25%)

Question 7

what are the probabilities of diatomic molecules of Cl₂?

Answer 7

Cl-35Cl-35 + (70)
Cl-35Cl-37 + (72)
Cl-37Cl-35 + (72)
Cl-37Cl-37 + (74)

Question 8

what’s the ratio for Cl diatomic molecules?

Answer 8

9:6:1

Question 9

what are the two isotopes of Br2?

Answer 9

Br-79 (50%) and Br-81 (50%)

Question 10

what are the probabilities of diatomic molecules of Br2?`

Answer 10

Br-79Br-79 + (158)
Br-79Br-81 + (160)
Br-81Br-79 + (160)
Br81Br-81 + (162)

Question 11

what’s the ratio for Br diatomic molecules?

Answer 11

1:2:1

Question 12

uses of mass spectrometers

Answer 12

• included in planetary space probes so that elements on other planets can be identified. elements on other planets can have a different composition of isotopes
• drug testing in sport to identify chemicals in the blood and to identify breakdown products from drugs in the body
• quality control in pharmaceutical industry and to identify molecules from sample with potential biological activity
• radioactive dating to determine age of fossils or human remains