1.5 Analytical Techniques

Question 1

why must an element become an ion before it can be analysed in a mass spectrometer?

Answer 1

• helps accelerate them as they pass the negative plates
• helps deflect them as they pass through the magnetic field as they are deflected due to mass to charge ratio

Question 2

what are the 5 stages of mass spectrometry?

Answer 2

Victor Is A Daft Duck
V - Vaporization
I - Ionization
A - Acceleration
D - Deflection
D - Detection

Question 3

Formula to calculate relative atomic mass (Ar)

Answer 3

Ar= (isotopic mass * atomic abundance)/100 + (isotopic mass * atomic abundance)/100 + …

Question 4

what is the formula for % abundance?

Answer 4

% abundance = (height of peak/total peak height) * 100
OR
solve for x when given all else:
- isotopic mass * (100-x)/100 + (isotopic mass * x) /100

Question 5

What are some limitations to the flame test?

Answer 5

• some metal ions generate the same colour
• colour can be subjective
• some ions do not produce any colour at all

Question 6

how does the flame test work?

Answer 6

Ground state:
- normal electron configuration before placed in the flame

Excited state:
- electron has absorbed energy to move to a higher energy level

Ground state:
- returns to the normal grounded state as it released the photon of light (colour)

Question 7

how does the emission spectra work?

Answer 7

• hot gas produces excited electrons that release a photon of light
• looks at the photon released when electron returns to grounded state

Question 8

how does the absorption spectrum work?

Answer 8

• cold gas exposed to a light source excites the electrons and they absorb energy
• looks at the wavelength that is absorbed when the electrons are moving to their excited state