C2 Specimen

Question 1

Inital rate of reaction in this experiment has the value 4.57x10-6
Use this value together with a rate obtained from your tangent to justify that the order of reaction is 2 with respect to butandiene

Answer 1

Find gradient
Inital rate/gradient = (2.23)

Initial concentration at point where tangent
0.018/0.012 = 1.5

If order 2 rate should increase (1.5)2 = 2.25
Approximately 2.23
So 2nd order with respect butadiene

Question 2

What would you do if you need to find Mr with two different isotopes (35Cl) and (37Cl)
C8H17Cl

Answer 2

C8H17(35Cl) = 148
C8H17(37Cl) = 150
148.8

Question 3

Explain the origin of the interaction representation by the dotted lines

Answer 3

Hydrogen bonding between O- and H+
N and O are both very electronegative
C=O N-H are polar
Lone pair strongly attracted to H+

Question 4

State the name of the sugar molecule that is attached to the bond at X

Answer 4

2-deoxyribose

Question 5

Suggest which of the bases A and B forms a pair with guanine when messenger RNA is synthesised

Answer 5

Base A
Top N-H forms H-bonds to lone pair on O of guanine
Lone pair of electrons on N bonds to H-N of guanine
A lone pair of e- on O bonds to lower H-N

Question 6

The minimum quantity of hot water was used why

Answer 6

To ensure hot solution would be saturated

Question 7

The crystals were compressed in the funnel why

Answer 7

Air passes through sample and not round it

Question 8

NO2 -> NH2 reagents

Answer 8

Sn/HCl

Question 9

NMR how to describe (decimal integration levels)
IR and NMR

Answer 9

IR radiation (O-H) alcohol 3230-3550
Talk about the peaks different H environments
Convert decimal points to whole numbers
Talk about singlet (splitting)

Question 10

Butanone is reduced in a two step reaction using NaBH4 followed by dilute HCl
Write overall equation for the reduction of butanone using [H] to represent the reducant

Answer 10

CH3CH2COCH3 + 2[H] -> CH3CH2CXH(OH)CH3

Question 11

By considering the mechanism of the reaction, explain whhy the product has no effect on plane polarised light

Answer 11

Nucleoophilic attack
Planar carbonyl grouyp
H- attacks from either side

Product of step 1 shown
Two chiral forms
Equal amounts of enatiomer
Optical isomer rotate plane in opposite directions
With racemic mixture