HHoonngg KKoonngg DDiipplloommaa ooff SSeeccoonnddaarryy EEdduuccaattiioonn
CChheemmiissttrryy && CCoommbbiinneedd SScciieennccee ((CChheemmiissttrryy ppaarrtt))
DDeecceemmbbeerr 22000088
Programme
Registration
Introduction
Contents
T M Li
Speakers Duration (min.)
20
10
Sample Papers Structure T M Li 20
Sample Questions for Electives W H Fong 15
SRR Exemplars
BREAK
SRR Level Descriptors
K C Pun
T M Li
15
20
10
SBA Requirements T M Li 25
Q & A ALL 45
2
3
Papers Sections Parts Topics
examined Questions Questions Sections Papers
Paper 1 (2.5
hours)
Section A
(18%)
Part I Topics 1-8 24 M.C.
24 M.C. Section A (12%)
One paper only (100 mins)
Part II Topics 1-12* 12 M.C.
Section B
(42%)
Part I Topics 1-8
structured questions
(47 marks) essay (9 marks)
structured questions
(47 marks) essay (9 marks)
Section B (28%)
Part II Topics 1-12* structured questions
(28 marks)
Paper 2 (1 hour)
20% Topics 13-15#
structured questions
20 marks per elective (40 marks)
SBA 20% 10% SBA
Total 100% 50% Total
Chemistry Combined Science (Chemistry Part)
NSS Chemistry Public AssessmentNSS Chemistry Public Assessment
* Emphasis would be put on Topics 912
# May include contents of Topics 112
CChheemmiissttrryy
Papers Sections Parts Topics
examined Questions
Section A Part I Topics 1-8 24 M.C.
Paper 1 (18%) Part II Topics 1-12* 12 M.C.
(2.5 hours)
Section B Part I Topics 1-8
structured questions (47 marks)
essay (9 marks)(42%)
Part II Topics 1-12* structured questions
(28 marks)
Paper 2 (1 hour)
20% Topics 13-15# structured questions
20 marks per elective (40 marks)
SBA 20%
Total 100%
* Emphasis would be put on Topics 912
# May include contents of Topics 112 4
CCoommbbiinneedd SScciieennccee ((CChheemmiissttrryy PPaarrtt))
Papers Sections Questions
One paper only (100 mins)
Section A (12%) 24 M.C.
Section B (28%)
structured questions (47 marks)
essay (9 marks)
SBA 10%
Total 50%
5
6
Sample Papers Structure
Multiple Choice
1. All MC items appear in Comb Sci (Chem) also appear in Chemistry 2. 23 MC items of Comb Sci (Chem) come from Part I of Chemistry, and
1 MC item of Comb Sci (Chem) comes from Part II of Chemistry (i.e. Q.19 of Comb Sci (Chem) = Q.27 of Chemistry)
Conventional Question
1. 52 out of 56 marks of Comb Sci (Chem) come from Chemistry 2. Only 4 marks (Q.5) in Comb Sci (Chem) do not come from Chemistry 3. The same paragraph-length/ essay question is asked in
Comb Sci (Chem) and Chemistry
Questions for the Combined Science (Chemistry part) will be, as far as possible,
extracted from those of the Chemistry
Chemistry-Paper 2 (Electives)
One question is set for each of the three electives, candidates are required to answer any 2 out of them.
7
Industrial Chemistry
1(c) The reaction for the production of methylpropene from 2-bromo-2-methylpropane is represented by the following equation :
CH3 CH3
H3C C CH3 + C2H5ONa → H3C C CH2 + C2H5OH + NaBr
Br
(i) With reference to green ceconomy of the reaction.
hemistry, calculate the atom
Answer: Atom economy
= molar mass of desirable product / sum of molar masses of all products = molar mass of methylpropene /(MM of methylpropene+ethanol+sodium bromide) = 56/(56+46+102.9) x 100% = 27.3% (2 marks)
8
9
Industrial Chemistry
(ii) Apart from atom economy, suggest TWO other factors that scientists should consider in order to conduct a green production process.
Answer:
Examples of other factors (Any TWO):
Waste Minimisation at Source
Use of Catalysts in place of Reagents
Use of Non-Toxic Reagents
Use of Renewable Resources
Use of Solvent Free or Recyclable Environmentally Benign Solvent systems (2 marks)
10
2(a) The structure of compound A , which exhibits liquid-crystalline behaviour, is shown below :
O
O
(i) Compound A can be formed by condensation of benzoic acid with cholesterol. Draw the structure of cholesterol.
Materials Chemistry
OH
Answer:
(2 marks)
Materials Chemistry
(ii) What is the difference between ‘true liquid’ and ‘liquid crystal’ ?
Answer: Molecules in ‘true liquid’ have no intrinsic order.
Molecules in liquid crystal possess some degree of translational freedom with certain orientation preference in one or two direction(s).
(2 marks)
(iii) Describe briefly the arrangement of the molecules in cholesteric phase liquid crystals.
Answer: The molecules line up in positions that they are slightly twisted from the molecules next to them giving rise to a helical-like arrangement.
(2 marks)
11
Materials Chemistry
(iv) Outline the working principle of cholesteric phase liquid crystals in Liquid Crystal Display (LCD).
Answer: In LCD, liquid crystals are packed between a polariser and an analyser.
When light passes through the polarizer, it will be polarised in the direction allowed by the polariser.
The polarised light will be guided by the molecules in each layer of the liquid crystals.
The polarised light is rotated by the desired angle and hence can pass through the analyser to give rise to bright region on the LCD.
(4 marks)
12
100
50
Analytical Chemistry 3(a) Compound G , with relative molecular mass of 58, has the following
composition by mass : C : 62.1% H : 10.3% O : 27.6% The infrared and mass spectra of compound G are given below.
100
80
4000 3000 2000 1500 1000 500 Wavenumber / cm–1
10 20 30 40 50 60 70
Rel
ativ
e In
tens
ity
60
40
20
00
Characteristic Infra-red Absorption Wavenumber Ranges (Stretching modes)
Bond Compound type Wavenumber range /cm–1
C=C Alkenes 1610 to 1680
C=O Aldehydes, ketones, carboxylic acids and derivatives 1680 to 1800
C≡C Alkynes 2070 to 2250
C≡N Nitriles 2200 to 2280
O–H Acids (hydrogen-bonded) 2500 to 3300
C–H Alkanes, alkenes, arenes 2840 to 3095
O–H Alcohols, phenols (hydrogen-bonded) 3230 to 3670
N–H Amines 3350 to 3500 13
Analytical Chemistry
(i) Deduce the molecular formula of compound G .
Answer: number of carbon atoms = 0.621(58)/12 = 3 number of H atoms = 0.103 (58)/1 = 6 number of O atoms = 0.276 (58) / 16 = 1 Molecular formula of G is C3H6O. (2 marks)
(ii) From the given spectral information and the molecular formula obtained in (i), deduce the structural formula of compound G.
Answer: From the IR spectrum, the presence of a sharp absorption peak at 1740 cm–1 indicates the presence of a carbonyl group.
From the mass spectrum, the peaks at m/e 29 corresponds to C2H5+ and
the peak at m/e 58 corresponds to CH3CH2CHO+.
The structural formula of G should be CH3CH2CHO. (4 marks) 14
Analytical Chemistry
(iii) Suggest an experiment, with detailed procedures, to support the structure of compound G you have deduced in (ii).
Answer: Add 2,4-dinitrophenylhydrazine to G to prepare the corresponding 2,4-dinitrophenylhydrazone.
Recrystallize the 2,4-dinitrophenylhydrazone.
Measure its melting point using a melting point apparatus.
A sharp melting point which is the same as that quoted in the literature will support the deduction of G.
(4 marks)
15
SSttaannddaarrddss RReeffeerreenncceedd RReeppoorrttiinngg ((SSRRRR))
� The standards are held constant � The percentage of students awarded a
given level may vary from year to year � The standards are more informative � Level descriptors together with exemplars
can better reflect the standards
16
SSttaannddaardrdss sseettttiinngg • Based on examination results, candidates are awarded
with a total score • To determine the minimum scores (also known as cut
scores) a candidate must obtain for meeting various standards (Levels 1-5)
17
18
Level DescriptorsLevel Descriptors The typical performance of candidates atThe typical performance of candidates at LevelLevel 55 :
DRAFT
� demonstrate comprehensive knowledge and understanding of facts, concepts and principles in chemistry
� apply the concepts of chemistry to a wide range of unfamiliar situations
� analyse, synthesise and critically evaluate information from multiple perspectives and in an in-depth manner
� effectively and consistently communicate ideas in a succinct, logical and coherent manner with accurate use of scientific terminology and appropriate formats
� design and conduct scientific investigations, evaluate procedures, handle and analyse data collected, and draw valid conclusions
19
Level DescriptorsLevel Descriptors The typical performance of candidates atThe typical performance of candidates at LevelLevel 44 :
DRAFT
� demonstrate sound knowledge and understanding of facts, concepts and principles in chemistry
� apply the concepts of chemistry to unfamiliar situations
� analyse, synthesise and evaluate information from several perspectives
� communicate ideas in a logical and coherent manner using scientific terminology and appropriate formats
� design and conduct scientific investigations, handle and interpret data collected, and draw conclusions
20
Level DescriptorsLevel Descriptors The typical performance of candidates atThe typical performance of candidates at LevelLevel 33 :
DRAFT
� demonstrate adequate knowledge and understanding of facts, concepts and principles in chemistry
� apply the concepts of chemistry to unfamiliar situations with guidance
� construct relationships and analyse information
� communicate ideas in a clear, structured manner using scientific terminology and appropriate formats
� design and conduct scientific investigations, handle and interpret data collected, and draw conclusions with guidance
21
Level DescriptorsLevel Descriptors The typical performance of candidates atThe typical performance of candidates at LevelLevel 22 :
DRAFT
� demonstrate basic knowledge and understanding of facts, concepts and principles in chemistry
� apply the concepts of chemistry to familiar situations
� describe relationships and handle information
� communicate ideas using appropriate scientific terms
� conduct practical work by following instructions, handle and interpret data collected, and draw simple conclusions
22
Level DescriptorsLevel Descriptors The typical performance of candidates atThe typical performance of candidates at LevelLevel 11 :
DRAFT
� recall elementary facts and principles in chemistry
� apply the concepts of chemistry to simple and familiar situations
� handle simple information presented in a straightforward manner
� communicate straightforward ideas using scientific terms
� conduct simple practical work by following instructions and collect the required data
TThhee 55 LLeevveellss ooff SSRRRR
• A panel of judges (experienced teachers, markers, examiners and university colleagues, etc.) determines the boundaries between levels with reference to 1. Level descriptors 2. Previous CE & AL results
• Annotated exemplars were selected to illustrate typical performance at each level.
23
25
Level 5 Exemplar DRAFT
Comments:
• Showing extensive knowledge and clear understanding on qualitative analysis by the use of appropriate reagents with accurate observations
• Showing excellent ability in logical and accurate presentation of chemical tests in a systematic way • Demonstrating effective communication skills using correct scientific terminologies such as flame
test and precipitate
27
Level 4 Exemplar DRAFT
Comments:
• Showing sound knowledge and clear understanding on drawing three-dimensional diagrams for diamond, and caesium chloride
• Showing ability in accurate explaining the electrical conduction of substances in terms of the availability of mobile ions and delocalized electrons
• Demonstrating effective communication skills such as using labeled diagrams
29
Level 3 Exemplar DRAFT
Comments:
• Showing adequate knowledge and understanding on three-dimensional structures of diamond and graphite • Communicating ideas with clear written expression on concepts related to electrical conductivity using
correct terminology such as ‘delocalization of electrons’ and ‘ions are not mobile’ • Showing some errors in using chemical terms such as ‘ionized electrons’ and was unable to draw three-
dimensional diagram in a careful manner
30
Level 2 Exemplar DRAFT
Comments:
• Showing basic knowledge on simple chemical reactions and the related observable changes such as the evolution of gas and the formation of precipitate
• Expressing simple chemical reactions by correct use of chemical formulae as exemplified by the reaction between zinc and dilute hydrochloric acid
• Showing some errors in balancing simple chemical equation as exemplified by the reaction between sodium hydroxide solution and iron(II) sulphate solution
31
Level 1 Exemplar DRAFT
Comments:
• Showing elementary knowledge and understanding on reaction between metal and dilute acid by giving an accurate observation
• Showing errors in balancing chemical equations
NNSSSS CChheemmiissttrryy SScchhooooll--bbaasseedd AAsssseessssmmeenntt
SBA TASKS
Weighting 20% of Public Assessment
Mode Practical Related Non-practical
Related
Task type
Basic Chemical Analysis
Experiment Investigative
Study Assignment
Task code
BCA EXPT IS ASSN
34
SSBBAA rreeqquuiirreemmeennttss
Number of assessments on SBA tasks
BCA EXPT IS ASSN
S6
≥1 ≥3 1 ≥1 S5
S4
35
SSBBAA rreeqquuiirreemmeennttss
Number of Experiments (including BCA & EXPT, but excluding IS)
S6
≥8 S5
36
NNSSSS CCoommbbiinneedd SScciieennccee ((CChheemmiissttrryy PPaarrtt)) SScchhooooll ––bbaasseedd AAsssseessssmmeenntt
SBA REQUIREMENTS Number of assessments on SBA tasks
Number of Experiments (including VA & EXPT)VA EXPT ASSN
S6 ≥1 ≥2 ≥1 ≥4
S5
37
Year of
examination Implementation of SBA
2012 and 2013
Schools are required to submit SBA marks for the practical related component only. The mark of this component will contribute to 20% of the final subject mark of CHEMISTRY and 10% of the final subject mark of COMBINEDSCIENCE respectively.
Note: In order to further alleviate the workload, marks of ‘Investigative Study’ of CHEMISTRY are NOT required in this stage.
2014 and thereafter
Schools have to submit SBA marks for both the practical and non-practical related components. The marks of both components will contribute to 20% of the final subject mark of CHEMISTRY and 10% of the final subject mark of COMBINED SCIENCE respectively.
38
Minimum number of assessments required for CHEMISTRY
Practical related task Non-practical related task
Basic Chemical Analysis (BCA)
Experiment
(EXPT)
Investigative Study
(IS)
Assignment
(ASSN)
2012 & 2013 exam
S5 1(8%) 1(4%) -- --
S6 -- 2(8%) -- --
2014 exam and thereafter
S5 1(4%) 2(4%) -- 1(4%)
S6 -- 1(2%) 1(6%) --
39
Minimum number of assessments required for COMBINED SCIENCE(CHEMISTRY part)
Practical related task Non-practical related task
Volumetric Analysis (VA)
Experiment (EXPT)
Assignment (ASSN)
2012 & 2013 exam
S5 1(4%) 1(3%) --
S6 -- 1(3%) --
2014 exam and thereafter
S5 1(3%) 1(2%) --
S6 -- 1(2%) 1(3%)
40
41
Teachers will be asked to submit a list of tasks done in S5 to S6, showing the coverage of the different types of work.
School repeaters / transfer candidates have to meet the respective minimum requirements for SBA in S6 as follows:
Year of examination
Minimum number of assessments required for CHEMISTRY
2013 2 EXPT (20%)
2014 and thereafter
1 EXPT (5%) and 1 IS (15%)
Year of examination
Minimum number of assessments required for COMBINED SCIENCE(CHEMISTRY part)
2013 1 EXPT (10%)
2014 and thereafter
1 EXPT (5%) and 1 ASSN (5%)
42
Switching of courses
Students who follow a science course with a Chemistry component (including Chemistry, Combined Science (Chemistry part) and Integrated Science) at S5 are allowed to switch to another one with a Chemistry component in their S6 year of study, provided that the school concerned is permitted to present candidates for the examination of the subject to be entered by the candidates. Such switching of courses is also allowed for school repeaters.
They are required to fulfill the same SBA requirements as those for school repeaters and transfer candidates
(i.e. S6 requirement)
43
Private Candidates
Private candidates will NOT need to complete the SBA component. Their subject mark will be based entirely on their public examination results and adjusted accordingly.
Private candidates who have SBA marks obtained in previous examinations are NOT allowed to carry these marks to the current examination.
44
HHooww ccaann sscchhoooollss ppllaann ffoorr SSBBAA IImmpplleemmeennttaattiioonn
� Conduct SBA as an integral part of teaching and learning and not treat it as an “add-on”
� Set up school’s own assessment plan, specify the no of assessment activities to be conducted for individual subjects
� Coordinate the conduct of the SBA across subjects so that students’ work will not be concentrated into one or two critical months
� Incorporate SBA as a part of schools’ internal assessment program and replace some of the current assessment activities, e.g. assignments, tests etc
45
PPrrooppoosseedd SSBBAA MMaarrkk SSuubbmmiissssiioonn CCoooorrddiinnaattiioonn aaccrroossss ssuubbjjeeccttss iinn 22001122 HHKKDDSSEE aanndd HHKKAALLEE ((DDrraafftt aass ooff OOcctt 0088))
1. 2011 (S5 for HKDSE and S6 for HKALE)
HKDSE HKALE
Mid May Early June Mid June Late June Early July Mid July Late June Early July
LS – Stage 1 DAT
ICT
Biology
Chemistry
Chi Lang
Integrated Science
History
Visual Arts
Chi History
Eng Lang
Chemistry Chinese Lang &
Culture
Physics
Combined Science
Chi Lit
2. 2012 (S6 for HKDSE and S7 for HKALE)
HKDSE HKALE
Mid Oct Mid Jan Early Feb Mid Feb Late Feb Early Mar Late Mar Early Mar Mid Mar Late Mar
LS – Stage 2 LS – Stage 3 History Physics ICT Chi Lang Eng Lang LS Physics Visual Arts
DAT
Visual Arts
Chemistry
Biology
Chi History
Integrated
Electronics
Computer
Chemistry
Biology
Chi Lang &
Culture
Combined
Science
Science Applications
Computer
GPA Chi Lit
Studies
46
PPrrooppoosseedd SSBBAA MMaarrkk SSuubbmmiissssiioonn CCoooorrddiinnaattiioonn aaccrroossss ssuubbjjeeccttss iinn 22001122 HHKKDDSSEE aanndd HHKKAALLEE ((DDrraafftt aass ooff OOcctt 0088))
2011
HKDSE HKALE
Mid June Chem (S5), Comb Sci (S5)
Late June Chem (S6)
HKDSE HKALE
2012 Mid February Chem (S6), Comb Sci (S6)
Mid March Chem (S7)
47
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