6.3.1 Chromotography and 6.3.5 NMR Spectroscopy

Question 1

2 types of chromatography

Answer 1

thin layer and gas

Question 2

Rf value equation

Answer 2

distance moved by spot/distance moved by solvent

Question 3

what is the stationary phase

Answer 3

in a fixed place
the molecules interact with stationary phase slow down movement

Question 4

what is the stationary phase for gas chromatography

Answer 4

liquid on solid support

Question 5

what is the mobile phase for gas chromatography

Answer 5

gas

Question 6

what is TLC used for

Answer 6

to check purity/monitor the extent of a reaction

Question 7

stationary phase of TLC

Answer 7

silica gel

Question 8

mobile phase of TLC

Answer 8

solvent

Question 9

when is the Rf value closer to one

Answer 9

when substances are very soluble in liquid

Question 10

limitations of Rf values

Answer 10

similar compounds have similar Rf values
unknown compounds have no Rf values for comparison
hard to find solvent that has correct amount of solubility

Question 11

how is separation achieved

Answer 11

by relative adsorptions of substances with the stationary phase

Question 12

what is gas chromatography used for

Answer 12

separate volatile compounds (gases) in a mixture

Question 13

what is a volatile compounds

Answer 13

gases so have low boiling points

Question 14

when is gas chromatography used

Answer 14

in forensic investigations

Question 15

retention time

Answer 15

time taken to pass through column

Question 16

what does chemical shift indicate

Answer 16

enviroments carbons are in

Question 17

3 things obtained from a carbon-13 NMR

Answer 17

number of different carbons
carbon environment
relative ratio of each types of carbons

Question 18

what is nucleur magnetic resource spectroscopy

Answer 18

technique used to probe the structure of molecules

Question 19

how are concentrations of components determined

Answer 19

comparing peak integration with values obtained from standard solutions of the component

Question 20

what is the area under the peaks on proton NMR proportional to

Answer 20

the number of protons