3.3.6 Organic Analysis

Question 1

Tollen’s reagent is formed by mixing aqueous ________ and ______/_______

Answer 1

Tollen’s reagent is formed by mixing aqueous ammonia and silver nitrate

Question 2

The active substance in Tollen’s reagent is the _______/___/__/_______

Answer 2

The active substance in Tollen’s reagent is the complex ion of [Ag(NH3 )2 ]+

Question 3

What is high resolution mass spectrometrry?

Answer 3

When a high resolution mass spectrometer can measure atomic and molecular masses to extreme levels of accuracy
It is used for distinguishing between compounds that have the same Mr when rounded to the nearest whole number

Question 4

How do molecular ion peaks change if the compound contains chlorine/bromine?

Answer 4

There will be two molecular ion peaks
Chlorine exists as Cl35 (75%) and Cl37 (25%)
Bromine exists as Br79 (50%) and Br81 (50%)

Question 5

Describe the technique of infrared spectroscopy

Answer 5

Certain groups in a molecule absorb
IR radiation at characteristic frequencies
Complicated spectra can be obtained that provide information about the bonds present

Question 6

What is meant by ‘‘fingerprinting’’ in organic analysis?

Answer 6

technique that allows for the identification of paritcular molecule by comparison of spectra
below 1500cm-1 - part of the spectrum is unique for every compound so is used as a fingerprint

Question 7

Summary: What are the methods of identifying each functional group? Give the reagent and the positive result
Alkene
Aldehyde (2)
Carboxylic Acid
1o 2o alcohol and aldehyde
Chloroalkane

Answer 7

ON GOOGLE DOC

Question 8

Write out the equation for the reaction of ethanal with Tollen’s reagent

Answer 8

CH3CHO + 2Ag+ + H2O -> CH3COOH + 2Ag + 2H+