organic analysis

Question 1

test for carboxylic acids

Answer 1

sodium carbonate
-if present solution bubbles
-effervescence

Question 2

test for alkene

Answer 2

bromine water
-brown to colourless

Question 3

answering which molecules more likely to produce fragment

Answer 3

-draw displayed formula
-draw ions that will form if bonds break and identify fragment in question

Question 4

m/z of CH3 +

Answer 4

15

Question 5

m/z of CN+

Answer 5

26

Question 6

m/z of C4H9 and C3H5O

Answer 6

57

Question 7

cause of abnormal peak on spectrometry

Answer 7

molecular ion containing different isotope

Question 8

why is the relative isotopic mass of carbon-12 exactly 12.00000

Answer 8

carbon-12 is used as the standard reference

Question 9

what happens when molecules absorb infrared light

Answer 9

the molecules at certain frequencies speed up

Question 10

what determines how molecules vibrate

Answer 10

molecules that contain more than one element vibrate differently
-more than one equals vibrate

Question 11

axis of infrared spectrum graph

Answer 11

transmittance- x axis
-wavenumber- y axis

Question 12

equation for wavelength

Answer 12

1/wavelength

Question 13

wavenumber unit

Answer 13

cm-1

Question 14

C-H absorption

Answer 14

around 3000

Question 15

C double C absorption

Answer 15

above 1600

Question 16

C double O carbonyls absorption

Answer 16

around 1700

Question 17

how to tell C-H absorption apart from O-H bonds

Answer 17

O-H thick like whale heads and C-H like mountain ranges

Question 18

alcohols apart from carboxylic acids on spectrum

Answer 18

alcohoks have smooth whale head curves and carbozylic acids have rough mountain ranges

Question 19

fingerpriny region

Answer 19

spectrum readings below 1500 are specific for each molecule so can identify a molecule

Question 20

justify why molecule chosen is the one and not other molecules exam question

Answer 20

-absorption caused by bond only in chosen molecule
-include wave number
-no peak for O-H in acid