WAEC - Chemistry (1994)

1
The components of universal indicator solution can best be separated by
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(A)
chromatography
2
The number of replaceable hydrogen atoms in one acid indicates its
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(A)
basicity
3
Catalytic hydrogenation of alkenes produces compounds with the general formula
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(C)
C_nH_2n+2
4
A measure of the degree of disorder in a chemical system is known as the
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(D)
entrophy
5
In any chemical reaction, the total mass of the products is always equal to that of the reactants. This is statement of the law of
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(B)
conservation of matter
6
Which of the following is not a property of magnesium oxide?
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(E)
Low binding energy
7
Which of the following would increase the rate of reaction of chips of a metal M as shown in the equation below? M_(s) + 2HCI_(aq) → MCI_2(aq) + H_2(g)
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(D)
Grinding the metal into powder
8
The oxidation number of phosphorus in \(PO_4^{3-}\) is
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(E)
+5
9
The number of atoms in 1.2g of carbon - 12 isotope is
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(B)
6.02 x 10₂₂
10
Tetraoxosulphate (lV) acid is described as strong acid because it is highly
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(E)
ionized in water
11
The following will decolourize acidified potassium tetraoxomanganate (VII) solution except
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(C)
pentane
12
Polyatomicity is illustrated by molecules of
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(A)
sulphur
13
Calcium is usually extracted by the electrolysis of its
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(E)
chloride
14
When naphthalene on heating changes from the solid state directly to the gaseous state it undergoes
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(B)
sublimation
15
Which of the following occurs when an aqueous solution of sodium hydroxide is electrolysed using graphite electrodes?
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(C)
Oxygen gas is produced at the anode
16
If the volume of a given mass of gas at 0^oC is 27.3cm³, what will be the volume of the gas at 10^oC, pressure remaining constant?
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(B)
28.3cm³
17
Glucose can be obtained from starch by
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(C)
hydrolysis
18
How many faradays of electricity are required to liberate 9g aluminium? (AI = 27)
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(C)
1.0
19
When water is dropped on calcium carbide, the gaseous product is an
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(C)
alkyne
20
Mg\(_2\) + 2HCI\(_{(aq)}\) → MgCI\(_{2(g)}\) + H\(_{2(g)}\).

From the equation above what mass of hydrogen would be produced if 12.0 g of magnesium reacted completely with dilute hydrochloric acid? (H = 1, Mg = 24)
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(A)
1.0g
21
The positive of an element in the Periodic Table is determined by
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(D)
the number of protons in its atom
22
Which of the following electronic structures belongs to a noble gas?
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(C)
1s²2s²2p⁶3s²3p⁶
23
In a chemical reaction, the reacting species possess energy of motion known as
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(D)
kinetic energy
24
The following compounds will decompose on heating except
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(B)
K₂CO₃
25
Which of the following reactions is accompanied by the first ionization energy of an element X?
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(D)
X _(g) → X⁺ _(g) +^e-
26
What is the molar of hydrogen sulphide gas in the reaction H₂SO_4(aq) + 3H₂S_(g) → 4S_(s) + 4H₂O _(l)n represented by the following equation?
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(A)
Reducing agent
27
Alkanols have unexpectedly high boiling points relative to their molar masses because of intermolecular
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(A)
hydrogen bonding
28
Sodium chloride is used in the following processes except in the
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(A)
treatment of polluted water
29
The gaseous product formed when ammonia is passed over heated copper (ll) oxide is
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(B)
nitrogen
30
Which of the following is not a halogen?
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(A)
Silicon
31
Which of the following is likely to have the highest degree of hardness?
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(E)
Lime water
32
Study the reaction represented by the equation: Alkanol + Alkanoic acid + conc. H\(_2\)SO\(_4\) → Alkanoate + water. The type of process involved in the reverse reaction is
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(C)
hydrolysis
33
Destructive distillation of coal means
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(C)
heating coal in the absence of air
34
When magnesium ribbon burns in air, the products are
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(C)
magnesium oxide and steam
35
The following compounds contain the same type of bonds except
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(B)
hydrogen chloride