Which of the following equimolar solutions will have the highest pH?
Răspuns
(B)
NaOH
2
Which of the following ions require the largest quantity of electricity for discharge at an electrode?
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(D)
2.0 moles of Al3+
3
Phenolphthalein in acidic solution is
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(C)
colourless
4
When iron is exposed to moisture and it rusts, the value of ΔG for the reaction is
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(D)
negative
5
In which of the following reactions can the oxidation number of the nitrogen be said to have increased?
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(A)
2NO(g) + O2(g) → 2NO2(g)
6
2H\(_2\) + O\(_2\) → 2H\(_2\)O ΔH = - 571kJ
In the equation above, how much heat will be liberated if 12.0g of hydrogen is burnt in excess oxygen?
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(D)
-1713 kJ
7
A concentrated solution containing H\(^+\), Cu\(^{2+}\), OH\(^-\) and Cl\(^-\) was electrolyzed using platinum electrodes.
The ion that will be discharged at the cathode is?
Răspuns
(A)
Cu2+
8
When sulphur (IV) oxide is passed into a solution of sodium hydroxide for a long time, it eventually produces a solution of
Răspuns
(B)
Na2SO3
9
What is the correct IUPAC name for NO\(_{2} ^{-}\)?
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(D)
Dioxonitrate (III) ion
10
What will happen if an aluminium spoon is used to stir a solution of iron (II) trioxonitrates (V)?
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(A)
The spoon will be oxidized while the iron (II) ions will be reduced to the metal
11
The enzymes responsible for converting sucrose into two simple isomeric sugars is
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(C)
invertase
12
The decolourization of purple colour of tetraoxomanganate (VII) ion is a test for
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(A)
alkenes
13
Which of the following are structural isomers?
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(B)
Propanal and propanone
14
In the purification of impure samples of ethyl ethanoate synthesized by esterification, concentrated sodium trioxocarbonate (IV) solution is used to remove
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(C)
acidic impurities
15
How many hydrogen atoms does a single ring cycloalkane have less than the corresponding open-chain alkane?
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(A)
Two
16
Equal moles of ethyne and hydrogen iodide react to give
Răspuns
(D)
CH2 = CHI
17
A substance that is used as a ripening agent for fruits is
Răspuns
(A)
ethene
18
When water boilers are used for long period of time, the solid substances left behind as scale are
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(A)
magnesium trioxosilicate (IV) and rust
19
25cm\(^3\) of a mixture of noble gases was obtained from air after the removal of other constituents. What was the original volume of air?
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(A)
2,500 cm3
20
The solubility curve shows the variation of solute concentration with
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(B)
temperature
21
The air around smelting industries is likely to contain
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(C)
H2, SO2 and CO2
22
Kerosene is commonly used to remove the red colour stain of palm oil from cloths because it
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(C)
makes the oil evaporate easily by dissolving it
23
The gas that is the most dangerous pollutant to human is
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(D)
hydrogen sulphide
24
Natural water collected from rivers and ponds contain oxygen, carbon (IV) oxide and
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(A)
nitrogen
25
How many moles of limestone will be required to produce 5.6g of CaO?
[Ca = 40, C = 12, O= 16]
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(B)
0.10 mol
26
The shape of the hydrocarbon compound CH\(_4\) is
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(D)
tetrahedral
27
Which of these properties gives a solid its definite shape?
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(A)
strong intermolecular attraction
28
Sugar is separated from its impurities by
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(B)
crystallization
29
The component of an atom that contributes least to its mass is the
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(D)
electron
30
An element will readily form an electrovalent compound if its electron configuration is
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(A)
2, 8, 1
31
A heterogenous mixture can be defined as any mixture
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(C)
whose composition is not uniform
32
The pressure of 100cm\(^3\) of oxygen at 35\(^0\)C is 750mmHg. What will be the volume of gas if the pressure is reduced to 100mmHg without changing the temperature?
Răspuns
(D)
750 cm3
33
I. Treatment of cancer II. Detection of leakages in water mains III. Detection of the ages of ancient tools IV. Preparation of drugs
Which combination of the above refers to the uses of radioactive isotopes?
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(D)
I, II, III and IV
34
What is the valence shell electron configuration of the element with atomic number 17?
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(D)
3s2 3p5
35
The density of a certain gas is 1.98gdm\(^{-3}\) at s.t.p. What is the molecular mass of the gas?
Răspuns
(A)
44.0 g
36
When pure aluminium metal is heated to red hot in the presence of nitrogen gas, the compound formed is
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(C)
AlN
37
A dense white fume is formed when ammonia gas reacts with
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(D)
HCl(g)
38
N\(_2\)(g) + 3H\(_2\)(g) ↔ 2NH\(_3\)(g) ΔH = - 90 kJ
In the equation above, the yield of ammonia can be decreased by
Răspuns
(C)
increase the temperature
39
The gas that can be dried using concentrated tetraoxosulphate (VI) acid is
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(B)
Sulphur (IV) oxide
40
NH\(_4\)Cl(s) ⇌ NH\(_3\)(g) + HCl(g)
The reaction above can only attain equilibrium if
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(C)
it is in a closed system
41
The most suitable metal that can be used as lightning conductor is?
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(B)
copper
42
In the diagram above which of the curves illustrates Arrhenius' law?
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(D)
X
43
The most abundant element on the earth's crust is
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(C)
oxygen
44
Metalloids are also referred to as
Răspuns
(A)
semi-metals
45
The ores that can be concentrated by flotation are
