U4AOS2 Quick Starter 1

In the mass spectrum of an organic compound, the

signal produced by the unfragmented molecular ion

and the signal produced by the most abundant particle

correspond respectively to the:

• parent (molecular) ion peak and main ion peak

• main ion peak and base peak

• parent (molecular) ion peak and base peak

• base peak and parent (molecular) ion peak.

How many peaks are expected in the HNMR spectra of ethyl ethanoate, CH3COOCH2CH3?

• 3

• 2

• 6

• 1

How many peaks are expected in the 13CNMR spectra of ethyl ethanoate, CH3COOCH2CH3?

• 4

• 3

• 2

• 1

The concentration of a substance is most

accurately determined in high-performance liquid

chromatography (HPLC) by measuring:

• peak height

• peak area

• retention time

• Rf value.

Amylase is an enzyme which catalyses the hydrolysis

of starch. An increase in temperature changes the

shape of the active site of amylase. This is because:

• the peptide links in the primary structure of amylase

  have been hydrolysed

• the enzyme has been denatured as intermolecular

  forces in the tertiary structure are broken

• only the hydrogen bonds holding the secondary

  structure of the enzyme together have been broken

• the increase in temperature increases the enzyme

  activity.