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NNaammee:: ______________________________ (( ))
CCllaassss:: ____________
TTooppiicc II –– PPllaanneett EEaarrtthh NNSSSS CChheemmiissttrryy 1111--1122
1. The atmosphere
2. The Ocean
3. Rocks and Minerals
MMrr.. RRiicckkyy TTssuuii
rriicckkyy..cchheemmiissttrryy@@ggmmaaiill..ccoomm
wwwwww..hhkksscciibblloogg..eedduubbllooggss..oorrgg
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Topic I – Planet Earth by Ricky Tsui
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Teaching content (from Curriculum and Assessment Guide, S4-6 Chemistry)
(1) Compulsory Part
Topic Suggested teaching hours
I. Planet earth 8 hours (4.0%)
II. Microscopic world I 24 hours (12.1%)
III. Metals 22 hours (11.1%)
IV. Acids and bases 27 hours (13.6%)
V. Fossil fuels and carbon compounds 20 hours (10.1%)
VI. Microscopic world II 8 hours (4.0%)
VII. Redox reactions, chemical cells and electrolysis 26 hours (13.1%)
VIII. Chemical reactions and energy 9 hours (4.5%)
IX. Rate of reaction 9 hours (4.5%)
X. Chemical equilibrium 10 hours (5.1%)
XI. Chemistry of carbon compounds 27 hours (13.6%)
XII. Patterns in the chemical world 8 hours (4.0%)
Total: 198 hours
(2) Elective Part (Select any 2 out of 3)
Topic Suggested teaching hours
XIII. Industrial chemistry 26 hours
XIV. Materials chemistry 26 hours
XV. Analytical chemistry 26 hours
Total: 52 hours
(3) Investigative Study (for taking 2014 examination and thereafter only)
XVI. Investigative study in chemistry 20 hours
Total: 20 hours
Assessment (from Curriculum and Assessment Guide, S4-6 Chemistry)
Component Outline Weighting Duration
Public examination
Paper 1 Compulsory Part 60% 2½ hours
Paper 2 Elective Part (a choice of two out
of three elective topics) 20% 1 hour
School-based assessment
(SBA)
Practical related tasks and non-practical
related tasks 20% N/A
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Topic I – Planet Earth by Ricky Tsui
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(Extracted from Curriculum and Assessment Guide, S4-6 Chemistry)
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Topic I – Planet Earth by Ricky Tsui
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1. The Atmosphere
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Topic I – Planet Earth by Ricky Tsui
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1. The Atmosphere
Composition of air
Air is a m of gases making up the atmosphere.
The approximate composition of air (by volume):
Composition Percentage by volume
Nitrogen
Oxygen
Noble gases
Carbon dioxide
Water vapour variable
Separation of oxygen and nitrogen
Oxygen and nitrogen can be separated from air by f d
of liquid air because they have different b p .
Noble gases can also be obtained by fractional distillation of liquid air.
(from Curriculum and Assessment Guide, S4-6 Chemistry)
How to separate O2 and N2 from the air? Base on what difference?
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Topic I – Planet Earth by Ricky Tsui
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Steps of fractional distillation of liquid air:
i) Air is purified to remove dusts, carbon dioxide and etc.
ii) Purified air is cooled to about -200 °C. The air changes to liquid at this
temperature.
iii) The liquid air is warmed up slowly.
iv) Nitrogen (b.p. = -196 °C) boils and is separated from the mixture first.
v) Oxygen (b.p. = -183 °C) boils and is separated from the mixture at a
_____________ temperature.
[10CE/MC]
[05CE/MC]
3. The table below gives some information about certain components in a sample of liquefied air.
Component Boiling point/oC
argon -186
nitrogen -196
oxygen -183
In what order are these components distilled out when the sample undergoes fractional distillation?
A. nitrogen, oxygen, argon
B. nitrogen, argon, oxygen
C. oxygen, argon, nitrogen
D. oxygen, nitrogen, argon
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Test for oxygen
Oxygen r a g s .
Note: Oxygen is not tested by burning splint.
_____________ splint is used to test hydrogen.
A ‘______’ sound will e given out.
[10CE/4(a)/ 1 mark]
Suggest a test for O2 Remember: “how” + “result”
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2. The Ocean
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Topic I – Planet Earth by Ricky Tsui
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2. The Ocean
Composition of sea water
Sea water is a mixture of salts,
dissolved gases, water, etc.
The approximate composition of sea water
(by mass):
Composition Percentage by mass
Water 96.5
Sodium chloride 2.4
Magnesium chloride 0.5
Sodium sulphate 0.4
Calcium chloride 0.1
_____________________ (common salt) and ___________
are two important components of sea water.
Extraction of common salt from sea water
To extract sodium chloride (common salt) from sea water,
1. f____________,
2. e_____________
3. and c_______________ are employed.
Filtration is a method for separating _______________ solid from a liquid.
(from Curriculum and Assessment Guide, S4-6 Chemistry)
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We can separate mud from sea water by f________________:
set-up for filtration
R____________: Solid remains in the filter paper.
F____________: The liquid that passes through the filter paper.
After filtration, sodium chloride is obtained from the sea water (filtrate) by
evaporation or crystallization.
Evaporation is a method for separating ______________ solid from a solution.
When sea water is evaporated to dryness, sodium chloride is left.
!?
Draw a labeled diagram for filtration set-up.
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Note:
The sodium chloride obtained is in powder form.
The sodium chloride obtained may contain some impurities, e.g. other minerals in
sea water.
C__________________ is a method used to obtain pure dissolved solid (solute)
from a solution.
Pure sodium chloride crystals can be obtained from a saturated solution of sea
water:
i) Warm the filtrated sea water in an evaporating dish until a saturated solution is
obtained.
ii) Cool the solution slowly. Large sodium chloride crystals are obtained.
iii) Filter off the crystals. Wash them with small amount of cold water and dry them
with filter paper.
growing sodium chloride crystals
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A s______________ solution is a solution containing the m_____________
amount of solute (sodium chloride) at a certain t_______________ .
Small crystals are obtained if the solution is cooled quickly.
Filtration can be employed to separate a solute from a solution.
[10CE/MC]
[09CE/7(a)/2 marks]
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Isolation of pure water from sea water
Simple distillation is a method for separating pure liquid from a solution.
Pure water can be obtained by simple distillation of sea water using simple
apparatus or 'Quickfit' apparatus.
Distillation using simple apparatus:
Thermometer is used to measure the temperature of the vapour (steam)
actually distilled over. Hence the thermometer bulb should be placed at the
opening of the delivery tube.
Anti-bumping granules are added to ensure smooth boiling.
The end of the delivery tube should be placed above the distillate. Otherwise,
sucking back of cold distillate into the hot boiling tube will occur if the heat source
is removed. This may crack the hot boiling tube.
Condenser is used to condense the steam.
How to prevent sucking back?
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fractional distillation set-up using “Quickfit” apparatus A box-set of “Quickfit” apparatus
Drawing distillation set-up
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Test for substances in sea water
Test for sodium
Flame test is used to show the presence of metals in some compounds.
Different metals give different flame colours.
Procedures of the flame test for sodium:
i) A clean platinum wire is dipped into concentrated hydrochloric acid.
ii) It is then dipped into powdered sodium chloride.
iii) The wire is heated in Bunsen flame.
Flame colours for compounds containing metals:
Compounds containing Flame colour
Sodium
Potassium
Calcium
Copper
[05CE/MC]
5. When a flame test is performed on copper(II) chloride, what is the colour of the flame observed ?
A. golden yellow
B. pale purple
C. brick-red
D. bluish-green
How to carry out flame test? Color of different flames?
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Test for chloride
Procedures for showing the presence of chloride in a solution:
i. Excess dilute nitric acid is added to the solution
ii. Silver nitrate solution is then added to the solution.
test for chloride ions
(We can also mix excess dilute nitric acid and silver nitrate solution first to give
acidified silver nitrate solution.)
In the presence of chloride, white precipitate is formed.
Ag+(aq) + Cl-(aq) AgCl(s)
colourless colourless white precipitate
Excess dilute nitric acid prevents formation of other white insoluble
compounds (e.g. silver carbonate and silver sulphite) which may mislead
the result.
How to test the presence of Cl-(aq)
Equation for ppt. formation
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Test for water
Water turns dry cobalt(II) chloride paper from blue to pink.
Water can also turn anhydrous copper(II) sulphate from white to blue.
The colour change of dry cobalt(II) chloride paper or anhydrous copper(II)
sulphate only shows the presence of water in a sample. It does not show
that the sample is pure water.
[10CE/2(b)(ii)/2 marks]
How to test the presence of water?
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3. Rocks and Minerals
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3. Rocks and Minerals
Rocks
The substances which make up rocks
are called minerals.
A mineral is a naturally occurring substance
(element or compound) with definite chemical composition.
Most rocks are mixtures of minerals.
Extraction of metals from their ores
An ore is a rock containing the mineral from which a particular m_______ can be
obtained.
Examples of some common ores:
Ore Metal in the ore
Haematite
Bauxite Aluminum
Copper pyrite
different kinds of metal ores
(from Curriculum and Assessment Guide, S4-6 Chemistry)
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The main steps involved in getting a metal from its ore:
i) M__________ of the ore (digging the ore from the ground)
ii) Separation of the useful mineral from waste
iii) E___________ of the metal from the mineral, e.g.
Physical separation such as p___________ for gold
H__________________________
Heating the ore with c__________ (carbon reduction)
E_____________ of molten ore
iv) Purification of the impure metal
gold panning iron-making blast furnace electrolysis of molten lead (II) bromide
Name of method for extracting metal from its ores
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Limestone, chalk and marble
L_____________(石灰石), c________(白堊) and m_________(大理石) are three
common materials in the Earth's crust.
They are different forms of c__________ c_____________.
limestone chalk marble
Chalk is the softest whereas marble is the hardest.
Uses of limestone, chalk and marble:
Forms of calcium carbonate Uses
Limestone
Cement Glass Materials for construction
Bauxite Materials for construction
Copper pyrite Making floor
[06CE/MC]
25. Which of the following substances contain calcium carbonate as the main chemical constituent?
(1) limestone
(2) chalk
(3) marble
A. (1) and (2) only
B. (1) and (3) only
C. (2) and (3) only
D. (1), (2) and (3)
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[10CE/MC]
Action of water, acid and heat on calcium carbonate
Action of water
Calcium carbonate is i________________ in water.
Action of acid
Calcium carbonate reacts with dilute hydrochloric acid to give calcium
chloride, water and carbon dioxide:
CaCO3(s) + 2HCl(aq) ___________________________________
Word equation: ______________________________________________
Observation:
Calcium carbonate dissolves to give a c______________ solution.
E_________________ (bubbles of carbon dioxide are evolved) occurs.
Action of heat
Calcium carbonate decomposes on heating to give c_________ o_________
(quicklime or lime) and carbon dioxide:
CaCO3(s) _______________________ [Q___________ (生石灰)]
Chemistry of calcium carbonate: 1. + water 2. + acid 3. heating
Writing word equation or chemical equation
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Word equation: ______________________________________________
When calcium oxide is added to water,
heat is released and c___________ h____________ (slaked lime) is formed:
CaO(s) + H2O(l) ___________________ [S_________ l_______ (熟石灰)]
Word equation: ______________________________________________
Calcium hydroxide is slightly soluble in water. The saturated calcium
hydroxide solution formed is called limewater.
water + Ca(OH)2(s) ____________________ (l_______ w________)
Word equation: ______________________________________________
quicklime slaked lime
Tests for calcium and carbonate in calcium carbonate
Calcium compounds give a b_______ r______ f_______ in the flame test.
Carbonate can be tested by adding dilute hydrochloric acid to the calcium
carbonate. The gas evolved (carbon dioxide) turns limewater milky due to
formation of insoluble calcium carbonate:
Ca(OH)2(aq) + CO2(g) ________________________
(Milky)
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.
[08CE/MC]
42. Calcium carbonate can be obtained from quicklime through two processes as shown below.
quicklime limewater calcium carbonate
Process 1 Process 2
Which of the following combinations is correct?
Process 1 Process 2
A. adding water adding Na2CO3(aq)
B. adding Na2CO3(aq) adding water
C. adding water heating
D. heating adding water
[04CE/MC]
11. A white solid is found around the mouth of a reagent bottle containing lime water. The white solid is
likely to be
A. calcium oxide.
B. calcium sulphate.
C. calcium carbonate.
D. calcium hydrogencarbonate.
Test for carbonate salt Set-up for limewater test
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[10CE/6(a)(b)(c)/5 marks]
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[09CE/1/5 marks]
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[05CE/1(a)(Ii)/2 marks]
1. (a) Calcium is an element in Group II of the Periodic Table.
(ii) Suggest a test to show that marble is a calcium-containing substance.
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