WAEC - Chemistry (2005)

1
The electronic configuration of an element X is 1s²2s ²2s⁶3p ² 3p⁴. It can be deduced that X
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(A)
Belongs to group 6 of the Periodic Table
2
What is the mass number of an element having 20 neutrons, 15 protons and 15 electrons?
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(C)
35
3
Which of the following sets of elements are arranged in order of decreasing atomic size in the Periodic Table?
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(B)
₄Be,₆ C,₇ N,₈ O
4
Which of the following changes is characteristic of an alpha-particle emission?
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(A)
the nucleus loses two protons and two neutrons
5
An element X has an atomic number of 16. What is its most likely oxidation state in its binary compounds?
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(B)
-2
6
An element which can exist in two or more forms in the same physical state, exhibits
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(C)
allotropy
7
Which of the following can be used to predict the type of bonding in HCI?
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(B)
Electronegativity difference
8
Which of the following molecules has a linear structure?
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(C)
CO₂
9
The volume occupied by a given mass of gas depends on its
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(B)
temperature and pressure
10
In which of the following reactions is the position of equilibrium not affected by an increase in pressure?
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(A)
3Fe_(s) + 4H₂O_(g) ⇌ Fe₃O_4(s) + 4H_2(g)
11
The activation energy of a reaction can be altered by
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(C)
using a catalyst
12
Which of the following factors does not affect the rate of reaction of CaCO₃ with HCI?
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(B)
solubility of the CaCO₃
13
When X is heated with manganese (IV) oxide, oxygen is produced X is
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(B)
KCIO₃
14
Which of the following statements is not a postulate of the kinetic theory of gases?
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(A)
Molecules move with the same speed
15
HNO3 does not usually react with metals to liberate hydrogen because HNO3 is
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(C)
an oxidizing agent
16
Which of the following is not an acid anhydride?
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(D)
CO
17
NaHCO_3(s) can be distinguished from Na₂CO_3(s) by the action of
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(D)
heat
18
What process is involved in the reaction represented by the following equation? AICI₃ + 3H₂O_(l) → AI(OH) _3(s) + 3HCI_(g)
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(B)
hydrolysis
19
A salt that absorbs moisture from the atmosphere without forming a solution is said to be
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(C)
hygroscopic
20
Consider the reaction represented by the equation below, xNH_3(g) + yCI_2(g) → zHCI_(g) + N_2(g) The values of x,y and z are respectively
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(C)
2, 3, 6
21
Which of the following compounds dissolves readily in water?
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(C)
NH₄CI
22
When ice is changing to water, its temperature remains the same because the heart gained is
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(A)
used to separate the molecules
23
Which of the following methods is suitable for preparing insoluble salts?
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(C)
Double decomposition
24
Which of the following reactions is sulphur (IV) oxidizing agent?
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(B)
2KMnO _4(aq) + 5SO_2(g) + 2H₂O → K₂SO_4(aq) +MnSO_4(aq) 2H₂SO_4(aq)
25
Which of the elements will burn in excess oxygen to form a product that is neutral to litmus?
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(B)
Hydrogen
26
The main difference between a primary cell and a secondary cell is that the primary cell
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(B)
cannot be recharged but the secondary cell can
27
Determine the mass of copper deposited by 4.0 moles of electrons in the reaction represented by the equation below: Cu²_(aq) + 2e^- → Cu_(s)
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(C)
128
28
Reaction undergone by compounds with the general formula C_n H_2n+2 include
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(C)
substitution
29
What is the major product formed when C₂H₅OH reacts with CH₃COOH?
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(C)
CH₃COOC₂H₅
30
Which of the following substances is a non-reducing sugar?
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(A)
Sucrose
31
The colour of the solution formed when ethyne reacts with an acidic solution of potassium tetraoxomanganate (VII) is
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(B)
colourless
32
Fats are classified as
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(B)
alkanoates
33
Ethyne undergoes the following reactions except
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(D)
esterification
34
Hardness in water can be removed by adding
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(B)
sodium trioxocarbonate (IV)
35
Which of the following pairs of solutions will produce a precipitate when mixed?
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(A)
Pb(NO₃)_2(aq) and NaCI_(aq)