7. • Name the process represented by the
equation.
• saponification
• Why are the soap molecules not effective in
hard water?
• soap ion react with Ca2+
/ Mg2+
ion
• to produce an insoluble salt / solid / scum
9. • Which pair of atoms are isotopes?
• P and R
• Give the reason for your answer in (a)(i).
• Both atoms have same number of protons but
different number of neutrons // Both atoms
have same proton number but different
nucleon number
10. Draw the electron arrangement for atom Q.
When metals of Group 1 react with water, bubbles of colourless gas are evolved.
Diagram 2 shows the reaction of the first three alkali metals with water
in three different beakers labeled as W, X and Y.
X
W X
Y
In which beaker shows the reaction of
potassium with water?
11. • Based on Diagram 2, name the gas evolved when
metals of
• Group1 react with water.
• hydrogen gas
• State one observation when a few drops of
phenolphthalein indicator is added into the
solution formed in W, X and Y.
• Explain your answer.
• Colourless solution turns pink
• The reaction produces alkaline solution
• a: presence of OH-
12. • Complete the following chemical equation:
• Lengkapkan persamaan kimia berikut:
• …… Na + …… H2O → ………..… + …………..
• Based on Diagram 2, what can you infer about
the density of Group 1 metals compared to
water?
• density of Group 1 metals are lower than the
density of water // less dense than water
13. Molten lead(II) oxide
Carbon F
Heat
Panaskan
Carbon G
Carbon L
Silver nitrate solution
Larutan argentum nitrat
Carbon M
Diagram 3.1
Rajah 3.1
Diagram 3.2
Rajah 3.2
What is meant by electrolyte?
A compound/substance that can conduct electricity in molten state or aqueous solution and undergoes chemical changes
14. • Name the product formed at electrode G.
• lead
• Write the half equation for the reaction that
occurs at electrode F.
• 2 O2-
O2 + 4e
• State the ions present in silver nitrate solutio
Ag+
, H+
, NO3
-
, OH-
(a: name of ions)
• n.
15. • What would you observe at carbon electrode
M?
• grey solid/ deposit
• Explain your answer in (c)(ii).
• Silver is produced// Ag+
is discharged
• Because silver ion is lower than hydrogen
ion in the Electrochemical Series
16. • Describe how you can verify the product formed
at carbon electrode L.
• Insert a glowing wooden splinter into the test
tube
• Glowing splinter will rekindles / relights /
reignites
• State one application of electrolysis in industries.
• Extraction of reactive metal / electroplating /
purification of metal
17. Type of acid
Jenis asid
Example
Contoh
pH
Strong acid
Asid kuat
Hydrochloric acid
Asid hidroklorik
1.0
Weak acid
Asid lemah
Oxalic acid
Asid oksalik
3.0
What is meant by a weak acid?
Acid (substance) which ionises partially// has lower degree
of dissociation in water to produce low concentration of
H+
ion
18. • Why is the pH value of hydrochloric acid lower
than the pH value of oxalic acid?
• The concentration of hydrogen ions in
hydrochloric acid is higher
• The higher the concentration of hydrogen
ions, the lower the pH value
19. Hydrochloric acid
Asid hidroklorik
25 cm3
of 0.1 mol dm-3
sodium hydroxide
25 cm3
natrium hidroksida 0.1 mol dm-3
Write a chemical equation to represent the
reaction.
HCl + NaOH NaCl + H2
O
20. • 25 cm3
of 0.1 mol dm-3
sodium hydroxide solution is required to react
completely with 12.50 cm3
of dilute hydrochloric acid.
• Calculate the molarity of the dilute hydrochloric acid used.
• ) No of mole of NaOH = 0.1 (25)
• 1000
• = 0.0025 mol
•
• 1 mol of NaOH react completely with 1 mol of HCl
• 0.0025 mol of NaOH react completely with 0.0025 mol HCl
•
• Molarity of HCl = 0.0025 x 1000
• 12.5
• = 0.2 mol dm-3
25 cm3
of 0.1 mol dm-3
sodium hydroxide solution is required to react
completely with 12.50 cm3
of dilute hydrochloric acid.
Calculate the molarity of the dilute hydrochloric
acid used.
21. Zinc oxide
Zink oksida
+ HCl
Step 1
Langkah 1
Solution N
Larutan N
Zinc carbonate
Zink karbonat
Sodium chloride
Natrium klorida
+
Step 2
Langkah 2
+ S
Name the following solutions:
Namakan larutan- larutan berikut:
4(c)(i)
N: ……………………..………
S: ..
……………………………
N : Zinc chloride
S : Sodium carbonate
r: formula
22. • State the type of reaction in Step 2.
• double decomposition/ precipitation
23. Burning lithium
Litium yang terbakar
Chlorine gas
Gas klorin
Write a chemical equation for the reaction.
) 2Li + Cl2 2LiCl
State the changes in oxidation number for
chlorine
0 to -1
Explain why lithium acts as the reducing agent
in terms of electron transfer.
) lithium atom loses // donates electron // is
electron donor
24. Bromine water
Air bromin
Potassium iodide solution
Larutan kalium iodida
A small amount of 1,1,1-trichloroethane liquid
is added to the product in the test tube and
the mixture is shaken.
What is the colour of 1,1,1-trichloroethane
layer?
purple
Write the ionic equation for the reaction
between bromine and potassium iodide
solution. Br2
+ 2I-
2Br -
+ I2
25. • What is the role of bromine water in this
reaction?
• oxidizing agent
26. Dry hydrogen gas
Gas hidrogen kering
Heat
Panaskan
Metal oxide powder
Serbuk oksida logam
27. Experiment
Eksperimen
Result
Keputusan
Hydrogen + oxide of metal J
Hidrogen + oksida logam J
Metal oxide powder glows brightly.
Black powder turned brown.
Serbuk oksida logam berbara dengan terang.
Serbuk hitam menjadi perang.
Hydrogen + oxide of metal T
Hidrogen + oksida logam T
No reaction.
Powder turns yellow when hot and white
when cold.
Tiada tindak balas.
Serbuk bertukar kuning apabila panas dan
putih apabila sejuk.
Hydrogen + magnesium oxide
Hidrogen + magnesium oksida
No reaction.
White powder remained.
Tiada tindak balas.
Serbuk putih kekal.
Suggest a name for metal T. ) zinc
28. • Arrange the reactivity of J, T, Magnesium and
Hydrogen in ascending order.
• J, H , T(zinc), magnesium
• Based on the observations, explain how you obtain the
arrangement
• Reaction occur between H2 and oxide J, so, H is
• more reactive than J
• 2. No reaction occur between H2 and oxide T and
• between H-2 and magnesium oxide
• so, H2 is less reactive than Mg and T
• 3. Magnesium is more reactive than zinc
29. Compound K Compound L
Write the general formula for the homologous
series of compound K.
CnH2n+1COOH, n= 0,1,2, ….
30. • Name compound L.
• Methyl propanoate
• Compare two physical properties of
compounds K and L by completing the
following table:
Physical property
Sifat fizik
Compound K
Sebatian K
Compound L
Sebatian L
Odour
Bau
Solubility
Keterlarutan
31. Properties Compound K Compound L
Odour pungent smell sweet/fruity smell
Solubility soluble in water //
soluble in organic
solvent
not soluble in water //
soluble in organic
solvent
32. • Compound L can be produced from K in the laboratory.
• Sebatian L boleh dihasilkan dari K di dalam
makmal.
•
• (i) Describe briefly how this process can be carried
out.
• Add methanol to compound K (propanoic acid) in a
boiling tube
• Add a few drops of concentrated sulphuric acid
• Heat gently / warm the mixture
33. • Write the equation for the reaction
• C2H5COOH + CH3OH C2H5COOCH3 + H2O
• Compound K is produced from the oxidation
of propanol.
• Draw all possible isomers for propanol.
34. t1 t2 Time,s
Masa
Volu
me of
gas,
cm3
Isipad
u gas
Compare the rate of reaction at t1 and t2.
Based on the graph, explain your answer.
Rate of reaction at t1
is higher than t2
2. because gradient at t1
is greater than t2
3. The concentration of hydrochloric acid decreases with
time
35. 2HCl + CaCO3
CaCl2
+ CO2
+ H2
O
The following chemical equation shows the reaction between calcium carbonate and hydrochloric acid.
Persamaan kimia berikut menunjukkan tindak balas antara kalsium karbonat dengan asid hidroklorik.
Determine the mass of calcium carbonate needed in the reaction if 480 cm3
of gas is released at room
condition.
(The molar volume of gas at room condition: 24 dm3
mol-1
,
Relative atomic mass: C = 12 g, O= 16 g, Ca = 40 g)
No of mole of gas = 480 / 24000 = 0.02 mol
From equation,
1 mol of CO2
is produced from 1 mol of CaCO3
0.02 mol of CO2
is produced from 0.02 mol of CaCO3
Mass of CaCO3
= 0.02 [40 + 12 + (16)(3)] g mol-1
= 2.0 g
36. Two experiments are carried out to study the effect of the size of calcium carbonate on the rate of reaction.
Dua eksperimen dijalankan untuk mengkaji kesan saiz kalsium karbonat ke atas kadar tindak balas.
Experiment I : 1 g of calcium carbonate chips react with 20.0 cm3
of 0.2 mol dm-3
hydrochloric acid.
Eksperimen I : 1 g ketulan kalsium karbonat bertindak balas dengan 20.0 cm3
asid hidroklorik 0.2 mol dm-3
.
Experiment II : 1 g of calcium carbonate powder react with 20.0 cm3
of 0.2 mol dm-3
hydrochloric acid.
Time / s
Masa/ s 0 60 120 180 240 300 360
Volume
of gas / cm3
Isipadu
gas / cm3
Experiment
I 0.00
25.9
0
33.0
0
37.0
0
40.5
0
42.0
0
42.0
0
Experiment
II 0.00
28.0
0
36.5
0
41.0
0
42.0
0
42.0
0
42.0
0
The volume of gas released is recorded in
Table 7.1
Isipadu gas yang terhasil direkodkan dalam
Jadual 7.1
•Plot a graph of volume of gas against time for both experiments in the graph paper provided on page 28.
Axis label & unit
All points transferred correctly
Curve – smooth curve, correct shape
Consistent scale
Label curve for both experiment
37. • Based on the graph, determine the rate of
reaction at 90 sec for Experiment I.
• Correct gradient drawn at t=90s
• Calculation, answer and unit (0.11 ± 0.03)
cm3
s-1
38. • Another set of experiment was carried out to
study the effect of temperature on the rate of
reaction between sodium thiosulphate
solution and sulphuric acid as shown in Table
7.2
Experiment
Eksperimen
I II
Temperature of sodium
thiosulphate / o
C
Suhu natrium tiosulfat
40 50
Write the ionic equation for the reaction.
S2
O3
2-
+ 2H+
S + SO2
+ H2
O
Correct formulae
Balance
39. • Compare the rate of reaction between
Experiment I and II by using Collision Theory.
• The rate of reaction in Experiment II is higher
than Experiment I
• 2. Temperature of sodium thiosulphate
solution in Experiment II is higher
• 3. Kinetic energy of particles in Experiment II
is higher,
• 4. frequency of collision between
thiosulphate ions and hydrogen ions higher
in Experiment II,
• [a: ions if the name of the ions is given in
40. • Based on the statement, explain the meaning of
ecorrect elements [ie: carbon and hydrogen]
• 2. The simplest ratio of mole/atom of carbon to
hydrogen is 2:5
• 3. The molecular formula shows the actual
number of carbon and hydrogen atoms in a
molecule
• 4. 1 molecule of butane contains 4 carbon
atoms and 10 hydrogen atoms.
• mpirical formula and molecular formula
The molecular formula of butane is C4H10
and its empirical formula is C2H5.
Formula molekul bagi butana ialah C4H10
dan formula empiriknya ialah C2H5
41. The decomposition of copper(II) nitrate is
shown in the following equation:
2 Cu(NO3)2 2 CuO + 4 NO2 + O2
(Relative atomic mass: N=14, O=16,
Cu=64,
molar volume of gas at room condition; 24
dm3
mol-1
)
Determine the percentage composition by
mass of oxygen in copper(II) nitrate.
% of oxygen
= 6(16) X 100 = 51.06 %
64 + 14(2) + 16(6)
Correct RMM shown
Calculation
and answer
42. • If 3.2 g of copper(II) oxide is produced during
the heating process, calculate the volume of
oxygen gas evolved at room condition.
• Number of mole of CuO = 3.2 = 0.04
mol
• 64 + 16
• 2 mol of CuO is released with 1 mol of O2
• 0.04 mol of CuO is released with 0.02 mol of
O2
• Volume of O2evolved = 0.02 (24) dm3
mol-1
• = 0.48 dm3
43. • A student carried out two experiments to
determine the empirical formulae for
magnesium oxide and copper(II) oxide.
• Diagram 8 shows the apparatus set-up for
both experiments.
Experiment I
Eksperimen I
Heat
Panaskan
Magnesium coil
Pita magnesium
Experiment II
Eksperimen II
Copper(II) oxide
Kuprum(II) oksida
Heat
Panaskan
Dry hydrogen
Hidrogen kering
44. Explain the differences in the method used
for the determination of the empirical
formulae for both oxides.
• Magnesium is a reactive metal
• 2. Magnesium can combine / react [readily]
with oxygen to form magnesium oxide
• 3. Copper is less reactive than hydrogen //
copper situated lower than hydrogen in
Reactivity Series
• 4. Hydrogen can reduce copper(II) oxide to
copper.
45. • The following equations show two redox
reactions involving iron(II) ion, Fe2+
.
• I 2 Fe2+
+ Br2 → 2 Fe3+
+ 2 Br-
• II Fe2+
+ Zn → Fe + Zn2+
• Compare the role of Fe2+
ion in both reactions.
• Explain your answer.
Reaction I Reaction II
role Reducing agent1
Oxidizing agent1
The oxidation number
of iron increases from
+2 to +3// Fe2+
loss
electron to form Fe3+
1
oxidation number of
iron decreases from +2
to 0 // Fe2+
gain
electron to form Fe
atom1
Fe2+
undergoes
oxidation1
Fe2+
undergoes
reduction1
46. • The reaction between sodium and chlorine
forms a compound with a high melting point.
• Determine the mass of the compound formed
when 2.3 g sodium reacts with excess
chlorine.
• [Relative atomic mass Na= 23, Cl= 35.5]
• 2Na + Cl2 2NaCl
• Number of mole of Na = 2.3 = 0.1
mol 23
•
• 2 mol of Na produce 2 mol of NaCl
47. Reaction
Tindak balas
Reactants
Bahan Tindak balas
Observation
Pemerhatian
I
Iron + Chlorine gas
Ferum + Gas klorin
The hot iron wool ignites rapidly
with a bright flame.
A brown solid is formed.
Wul besi panas menyala dengan cepat
dan terang.
Pepejal perang terhasil.
II
Iron + Bromine gas
Ferum + Gas bromin
The hot iron wool glows moderately
bright and moderately fast.
A brown solid is formed.
Wul besi panas berbara sederhana
terang dan sederhana cepat.
Pepejal perang terhasil.
Write the chemical equation for either of
the reactions.
) 2 Fe + 3Cl2 2FeCl3 or 2 Fe +
3Br2 2FeBr3
48. • Compare the reactivity of both reactions.
• Explain your answer.
• The reactivity of reaction I is higher than
reaction II.
• 2. The atomic size of chlorine is smaller
than bromine
• 3. The forces of attraction of the nucleus
toward the
• electrons is stronger in chlorine atom
than in bromine atom
• 4. It is easier for chlorine atom to attract
electron
49. • Diagram 9 shows the standard representation
for the atoms of three elements; Li, C and Cl.
Using the given information, describe the
formation of two compounds with different
types of bonding.
50. • . Electron arrangement of atom Li: 2.1, Cl:
2.8.7, C: 2.4
• Formation of compound between Li and Cl
• 2. To achieve stable electron arrangement
• 3. Lithium atom need to lose / donate 1
valence electron to form lithium ion // Li
Li+
+ e while
• 4. Chlorine atom need to gain 1 electron to
form chloride ion // Cl2 + 2e 2Cl-
• 5. Li+
ion attracted to Cl-
ion by electrostatic
force to form ionic bond
51. • 6. Diagram - correct number of electrons
and shells - shows Li+
ion and Cl-
ion
• Formation of compound between C and Cl
• 7. Carbon atom share valence electron with
chlorine atom
• 8. Each C atom contributes 4 electrons and
each Cl atom contributes 1 electron // each
C atom share electron with 4 Cl atom
• 9. To form #
4 single#
covalent bond
• 10. diagram - correct number of
electrons and shells
• - shows sharing electron
52. Mg + 2 HCl
ΔH = -50.4 kJ mol -1
Mg Cl2 + H2
Determine the temperature change when
50 cm3
of 1.0 mol dm-3
of
hydrochloric acid reacts with excess
magnesium.
[Specific heat capacity of
solution: 4.2 J g-1 o
C-1
,
density of solution: 1 g cm-3
]
53. • Mol of hydrochloric acid = 1 x 50
• 1000
• = 0.05 mol
• 2 mol HCl react to produce 50.4 kJ
• 0. 05 mol of HCl react to produce = 0. 05 x
50.4
• 2 = 1.26 kJ
• θ = H
• mc
• = 1.26 x 1000
• (50)(4.2)
54. Alcohol
Alkohol
Molecular Formula
Formula molekul
Heat of combustion/ kJ mol-1
Haba pembakaran
Propanol C3H7OH -2100
Butanol C4H9OH -2877
•Write the equation for the complete combustion of either one of the alcohol.
C3
H7
OH + 9/2O2
3CO2
+ 4H2
O
or
C4
H9
OH + 6 O2
4CO2
+ 5H2
O
55. • Compare the heat of combustion between
propanol and butanol.
• Explain your answer.
• Heat of combustion of butanol is higher than
propanol.
• 2. The number of carbon atom per molecule
butanol is bigger than propanol
• 3. Butanol produce more carbon dioxide and
water molecules than propanol // more
bonds are formed // energy content is higher
in butanol.
• 4. Released more heat energy
56. • Describe a laboratory experiment to
determine the heat of combustion of a named
alcohol.
• Your answer should include:
• a labeled diagram
• procedure
57. • Diagram:
• Arrangement of apparatus is functional
• can with water, thermometer, spirit lamp with
alcohol
• no wire gauze, thermometer not touching
surface, flame touching can
• Labeled water, alcohol, [metal] can
•
58. • Procedure:
• 1. (100-250 cm3
) of water is measured and
poured into a copper can and the copper can is
placed on a tripod stand.
• 2. The initial temperature of the water is
measured and recorded.
• 3. A spirit lamp with ethanol is weighed and
its mass is recorded.
• 4. The lamp is then placed under the copper
can and the wick of the lamp is lighted up
immediately.
59. • 5. The water in the can is stirred continuously
until the temperature of the water
increases by about 20- 50 o
C.
• 6. The flame is put off and the highest
temperature reached by the water is
recorded.
• 7. The lamp and its content are weighed and
the mass is recorded.
