Modern analytical Techniques

Question 1

Explain the steps of mass spec.

Answer 1

1. Vaporise the sample
2. Ionise the sample by firing high energy electrons at it, forming positive ions.
3. Accelerate ions through an electric field.
4. Ions are deflected more or less based on how heavy they are (the heavier the least deflection)
5. The peaks for each mass are determined in detections per unit of time.

Question 2

How do you determine relative atomic mass of a molecular ion from its ‘stick diagram’

Answer 2

Read of the largest m/z value ( the furthest right)

Question 3

What instruments are used in IR spec?

Answer 3

Spectroscopes (used more for observations) or Spectrometers (emphasises importance of measurements)

Question 4

What type of bonds absorb IR radiation

Answer 4

Polar

Question 5

What is on the axis of an absorption spectrum

Answer 5

Transmittance (Y) a percentage measure of amount if radiation let through; Wavenumber (X) the number of waves in 1 cm ranging from 400 to 4500/cm

Question 6

How are functional groups differentiated in IR- Spec?

Answer 6

Using the type of vibration e.g. whether its stretching or vibrating