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Title: OCR A level Chemistry Notes Topic: 2.1.5
Description: A level Chemistry Revision notes
Description: A level Chemistry Revision notes
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PMT
1
...
(i)
(ii)
Any two realistic fragments,
e
...
CH3+: 15; C2H5+: 29; C3H7+: 43; C4H9+: 57; OH+: 17, etc
...
2
breathalysers/monitoring of air pollution, MOT emission testing, etc
...
Availability of starting materials:
availability
sugar is renewable because it can be grown (1)
ethane is finite because it is obtained by processing of crude oil (1)
energy:
fermentation: energy is required for distillation/
hydration: energy is required to generate steam (1)
atom economy and waste products:
atom economy for fermentation < atom economy hydration (1)
In fermentation, CO2 is produced in addition to ethanol/ethanol is
not the only product (1)
In hydration, ethanol is the only product/hydration is an addition
reaction (1)
Atom economy of fermentation could be increased by finding a use
CO2 (1)
Atom economy linked to a chemical equation to show that hydration
has 100% atom economy/fermentation has 51% atom economy (1) 7max
[7]
PMT
4
...
(ii)
balanced equation
C6H12O6 (aq) → 2C2H5OH(l) or (aq) + 2CO2(g)
state symbols can be awarded only if equation shows C6H12O6 ,
C2H5OH and CO2
anaerobic, aqueous, temp range 25 − 40°C/warm to just above room temp
1
2
(iii)
no more bubbles/gas/CO2
1
(i)
1
[5]
6
...
O
...
CH3 H
H
H
step 3
H
C
C
...
...
CH3CH(OH)CH3 + 4½O2 → 3CO2 + 4H2O /C3H8O
(1 mark if correct formula for all four chemicals and 1 mark for
correct balancing)
[2]
8
...
H
H
C
C
C
H
C2H5
H
H
C
H3C
H
H3C
C
CH3
H
C
CH3
Minimum − must display/show C=C
[3]
10
...
(a)
(i)
1
Cl
(ii)
H2SO4/Al2O3/(hot) pumice/H3PO4
1
(H2SO4(aq) or dil H2SO4 loses the mark)
(iii)
1
OH
+ H 2O
C6H11OH / C6H12O → C6H10 + H2O
(b)
(i)
1
OH
OH
also allow
OH
Cl
diol
Cl-alcohol
PMT
(ii)
2
from the diol allow
from the Cl-alcohol allow
Cl
OH
[6]
12
...
= bonds/forces/attractions between molecules
1
1
(ii)
type of intermolecular bond = hydrogen bond
1
dipoles on both O-H bonds
1
H-bond shown as a ‘dashed bond’
1
H
H
C
H
H
C
δ–
O
H
δ+
H
H
H
C
H
δ–
O
C
H
H
δ+
(iii)
H
(The boiling point of glycerol will be higher than ethanol because there are)
more OH groups ∴ more H-bonds
1
[6]
13
...
(i)
Cr2O72-
H+
2
(ii)
compound E
compound F
H
H3C
C
C
CH2
H3C CH2 CH2
H
H3C
2[O]
C
OH
H2 O
COOH
H3C CH2 CH2
C 7 H 14 O
+
C
C 7 H 14 O2
3
(iii)
carboxylic acid would have an absorption between
1680 – 1750 cm-1 /1700 cm-1 or 2500 – 3300 cm-1
...
(a)
(i)
H2SO4 – any mention of (aq) loses the mark
1
(ii)
any correct formula/structure or name for benzoic acid
1
PMT
(b)
(i)
dichromate/Cr2O72–/permanganate
1
(ii)
1
OH
O
+ [O]
H2
C
+ H2O
H2
C
OH
H2C
CH
H2C
CH2
O
H2C
C
H2C
CH2
+ H2O
+ [O]
C
H2
C6H12O
C
H2
+ [O]
C6H10O
+ H2O
[4]
16
...
require at least one ‘wedge’ bond or one
‘dotted’ bond
(ii)
108 − 111°
1
(iii)
volatile/low boiling/gas/non-toxic/non-flammable/unreactive/liquefied under
pressure/inert
1
homolytic = bonded pair split equally/ each retains 1 electron
1
fission = bond breaking
1
(v)
C-Cl (no mark) because it is the weaker bond
1
(vi)
Cl•
1
•CF3 (allow CF3•)
1
(iv)
(lack of ‘dots’ penalise once)
[8]
17
...
H
δ+
O
H
H
C
H
H
C
H
δ–
O
H
H
C
C
H
H
H
H
dipoles
1
hydrogen bond between O in one O-H
and H in the other O-H
1
lone pair from O involved in the H-bond
1
[3]
19
...
(a)
(i)
reaction 1
1
(ii)
reaction 4
1
(iii)
reaction 3
1
PMT
(b)
(i)
lone pair/electron pair donor
H3C
CH2
δ+
1
δ-
CH2
Cl
H3C
CH2
CH2
OH
+
-
Cl
...
(same formula, different structure
...
(a)
(i)
prop-2-en-1-ol CH2=CHCH2OH must show the C=C double bond
1
acrolein
O
H2C
CH
C
H
must clearly show the aldehyde group and the C=C
1
(ii)
alkene/C=C double bond
1
PMT
(b)
(i)
(ii)
acidified /H+
1
dichromate/Cr2O7 2-
1
CH2CHCH2OH/ C3H6O/ C3H5OH + [O]
CH2CHCHO/ C3H4O/
C2H3CHO + H2O
not CH2CHCOH
1
[6]
22
...
COO/CO2 without displaying the ester, they can still get 1
mark
...
Essential marks:
Order
RI>RBr>RCl /owtte
1
reason for the order
C-I bond weakest/length/C-Cl bond strongest and
mention/intermolc forces loses the mark
1
Ag+ + XAgX (solid or ppt) or an equation for
hydrolysis/using OH- or H2O
1
an equation
max = 3
Two possible methods of monitoring the reaction
Method 1
Method 2
AgNO3
AgNO3
1
Ethanol & Waterbath/
/hydroxide
temp 40 − 80°C
not heat/not bunsen
NaOH/OH-
1
& neutralise with HNO3
relative amount of
precipitation
relative rate of
precipitation
1
[6]
24
...
(a)
H H H H
H C C C C H
H H OH H
H
H C
H
CH 3 H
C H
C
OH
H
H
CH3 H
H C
C
C H
H
H
OH
3
PMT
(b)
(i)
orange to green/dark green/brown/black
1
(ii)
C4H9OH/ C4H10O + 2[O] → C3H7COOH + H2O
2
1 mark available for correct formula of the carboxylic acid
(iii)
(c)
(d)
Identify isomer 2-methylpropan-1-ol by appropriate
number/name/formula
1
CH2 has mass = 14, 14 × 4 = 56
1
∴C4H8
1
(ii)
C4H9OH → C4H8 + H2O
1
(iii)
Identify butan-2-ol by appropriate number/name/formula
1
(i)
H2SO4
1
(ii)
0
...
x
50
0
4000
3000
2000
1500
1000
500
HAVENUMBER
(c)
(i)
Ni/Pt/Rh/Pd
1
PMT
(ii)
compound B is C10H22O
1
(iii)
C10H20O + H2 → C10H22O
1
[9]
27
...
1
C2H4 + H2O → C2H5OH
1
Temp > 100 °C/Press 370 − 100 atm
continuous process
/ 6 −20 MPa/phosphoric acid catalyst/
Glucose is obtained from plants
Ethene is obtained from crude oil/cracking/fossil fuel
glucose is renewable/ethene isn’t
1
1
1
1
1 mark available for Quality of written communication…
...
(a)
(b)
(i)
C4H10
1
(ii)
C2H5O
1
(iii)
B and E
1
(iv)
A and F
1
(C4H9OH →) C4H8 + H2O
1
PMT
(c)
1
any unambiguous formula:
H
H
C
H
C
C
H
C
H
H
H
C
C
H
H
C
C
H
H
H
CH 2 CHCHCH2
H
H
H
H
C
C
C
C
H
H
CH2CHCHCH2
buta-1,3-diene
name ecf to the structure only if structure above has formula C4H6
1
[7]
29
...
H
H
OH
CH3 CH2 CH2
CH3 CH2 CH2
H
(b)
(i)
C
OH
+ Cl
H
mark for method/dividing by Ar / C, 3
...
3; Cl, 1
...
1
divide by smallest to get C2H4Cl
1
alternative method:
% of each element x 127 ÷ Ar of that
element = molecular formula, hence deduce empirical formula
(ii)
C4H8Cl2
1
PMT
(iii)
any unambiguous form of:
H H H H
H C
C
C C OH
H OH H H
1
(iv)
any unambiguous form of:
H H H H
H C
C
C
C
Cl
H Cl H H
1
ecf to (iii) provided that there are two OHs in (iii)
[9]
30
Title: OCR A level Chemistry Notes Topic: 2.1.5
Description: A level Chemistry Revision notes
Description: A level Chemistry Revision notes