The number of orbitals in a p-sub level of an atom is
Răspuns
(B)
3
2
Which of the following electron configurations represents that of an atom in its ground state?
Răspuns
(D)
1s22s22p63s0
3
Which of the following ions has an electron configuration different from the other?
Răspuns
(A)
17CI-
4
The atomic radii of metals are usually
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(A)
greater than their ionic radii
5
Two elements, X and Y are in the same group on the periodic table because they both have the same
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(B)
number of valence electrons
6
The d-block elements are paramagnetic because they
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(B)
contain unpaired electrons in the partially filled 3d-orbital
7
Which of the following statements about a radioactive substance is/are correct? l. lt emits radiation continuously and spontaneously. ll. The emitted radiations are affected by temperature and pressure III. The radiation can penetrate opaque matter
Răspuns
(C)
l and lll only
8
Which of the following elements is a metalloid?
Răspuns
(C)
Silicon
9
Which of the following halogens is liquid at room temperature?
Răspuns
(D)
Bromine
10
The shape of a graphite crystal is
Răspuns
(C)
hexagonal
11
The complex compound formed by the combination of two elements with a large electronegativity difference is likely to be
Răspuns
(D)
ionic
12
The complex compound formed when aluminum dissolves in aqueous sodium hydroxide is
Răspuns
(B)
NaAl(OH)4
13
The vapour pressure of a liquid depends on l. temperature. ll. rate of condensation. III. cohesive forces holding the particles together
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(C)
l and lll only
14
MgO does not readily dissolve in water because
Răspuns
(D)
its lattice energy is higher than its hydration energy
15
Consider the following reaction equation: CaCO\(_{3(s)}\) + 2HCI\(_{(aq)}\) → CaCl\(_{2(aq)}\) + H\(_2\)O\(_{(l)}\) + CO\(_{2(g)}\). What mass of CaCI\(_2\) would be obtained when 25.0g of CaCO\(_{3(s)}\) is reacted with excess HCI\(_{(aq)}\)? [CaCO\(_3 = 100; CaCI\(_2\) = 111]
Răspuns
(D)
27.8 g
16
The number of sulphur atoms in 3.20g of SO\(_{2(g)}\) is [O = 16.0;S = 32.0; Avogadro constant = 6.02 x 10\(^{23}\)]
Răspuns
(A)
3.01 x 1022
17
Consider the reaction represented by the following equation: xCH\(_3\)OH + yO\(_2\) → 2CO\(_2\) + zH\(_2\)O. The values of x,y and z respectively, are
Răspuns
(A)
2,3 and 4
18
The formula of mercury (l) dioxonitrate (III) is
Răspuns
(C)
Hg2(NO2)2
19
A sample of a gas may be identified as chlorine if it turns
Răspuns
(D)
starch iodide paper blue-black
20
A metal M forms two types of chlorine, MCl\(_2\) and MCl\(_3\) which of the following laws best explains the relationship between the chlorides? Law of
Răspuns
(C)
multiple proportion
21
Which of the following metals would readily displace hydrogen from steam?
Răspuns
(C)
Magnesium
22
The volume occupied by 0.4 g of hydrogen gas at s.t.p. is [H = 1. 00; Molar volume at s.t.p. = 22.4 dm3]
Răspuns
(B)
4.48dm3
23
When a substance changes directly from the solid state to the gaseous state without forming a liquid, the substance is said to
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(C)
sublime
24
At ordinary temperature H\(_2\)O is a liquid while H\(_2\)S is a gas. This is because H\(_2\)O has
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(B)
strong hydrogen bonds holding its molecules together
25
The postulate that molecules are in constant random motion best explains why liquids
Răspuns
(A)
can undergo solidification
26
Which of the following gases has the lowest rate of diffusion under the same condition? [H = 1.00; He = 4. 00; O = 16.0; CI = 35.5]
Răspuns
(A)
CI2
27
The energy evolved when magnesium burns in air is in the form of
Răspuns
(C)
light and heat
28
A substance L reacts with NH\(_4\)NO\(_{3(aq)}\) to generate ammonia gas. L is likely to be
Răspuns
(B)
NaOH
29
On heating, the following trioxocarbonate (IV) salts decompose to give solid residue except
Răspuns
(A)
ammonium trioxocarbonate (IV)
30
Which of the following pH values indicates that a solution is a strong base?
Răspuns
(D)
13
31
The hydrolysis of NH\(_4\)CI gives
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(A)
an acidic solution
32
A spot of oil paint on a shirt can best be removed using?
Răspuns
(C)
kerosine
33
Consider the reaction represented by the following equation: CuO\(_{(s)}\) + H\(_2\)SO\(_{4(aq)}\) → CuSO\(_{4(aq)}\) + H\(_2\)O\(_{(l)}\). Which of the following factors will not affect the rate of the reaction?
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(D)
Pressure of reaction system
34
Which of the following devices function on redox reaction? l. Dry cell ll. Car battery III. Electric generator
Răspuns
(C)
l and ll only
35
The oxidation number of Fe in [Fe(CN)\(_6\)]\(^{3-}\) is
Răspuns
(A)
+3
36
Consider the following reaction equation: C\(_{16}\)H\(_{34}\) → C\(_5\)H\(_{12}\) + C\(_{11}\)H\(_{22}\). The process represented by the equation is
Răspuns
(A)
cracking
37
Which of the following substances would not produce ethanol when fermented?
Răspuns
(D)
Vinegar
38
An alkanol can be prepared by the reaction of an alkene with
Răspuns
(A)
concentrated tetraoxosulphate (VI) acid
39
A tertiary alkanol has a molecular formula C\(_4\)H\(_{10}\)O. What is the structural formula of the compound?
Răspuns
(C)
(CH3)3COH
40
Which of the following industrial processes depends on the action of enzymes?
