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WAEC - Chemistry (2015)

1
The negatively charged particle in an atom is the
Answer
(A)
Electron
2
How many orbits are contained in an atom with atomic number 13?
Answer
(D)
3
3
The Van der waals' forces are dominant intermolecular forces in_______?
Answer
(B)
Chlorine
4
The compound formed between 14X and 16Y is _______?
Answer
(B)
XY2
5
The shape of a molecule of water is _______?
Answer
(A)
Non-linear
6
A metallic ion Z\(^{2+}\) with an inert gas structure contains 18 electrons. How many protons are contained in this ion?
Answer
(A)
20
7
Which of the following pairs of elements forms amphoteric oxides?
Answer
(D)
Si and Pb
8
Which of the following pairs of compounds belongs to the same homologous series?
Answer
(D)
C2H6 and C4H10
9
The following transition metal ions would be coloured in aqueous solution except________?
Answer
(D)
Sc3+
10
The gas given off when ethanol reacts with sodium is
Answer
(B)
Hydrogen
11
Which of the following halogens is solid at room temperature?
Answer
(D)
Iodine
12
The alkaline earth metals have similar chemical properties because________?
Answer
(C)
They have the same number of valence electrons
13
The number of unpaired electrons in an atom of an element 8Q is _______?
Answer
(A)
2
14
The bond formed when ammonia reacts with hydrogen ion to form ammonium ion is
Answer
(B)
Dative
15
To which group and period respectively does an element with 15 electrons belong?
Answer
(C)
5 and 3
16
The shape of a graphite crystal is
Answer
(D)
Hexagonal
17
Which of the following oxides is ionic?
Answer
(B)
MgO
18
Which of the following substances when boiled with aqueous solution of sodium hydroxide would be hydrolyzed?

i. Protein ii. Fat iii. Polythene
Answer
(C)
i and ii
19
Which of the following trioxonitrate(V) salts would decompose on heating to form a metal?
Answer
(B)
AgNO3
20
Consider the following reaction equation:
C2H4(g) + 3O2(g) \(\to\) 2CO2(g) + 2H2O(g)

The volume of CO2(g) produced at s.t.p when 0.05 moles of C2H4(g) was burnt in O2(g) is
[Molar Volume of gas = 22.4dm3
Answer
(B)
2.24dm3
21
The number of oxygen molecules present in 16.0g of the gas is ______?
[Avogadro's number = 6.02 x 1023]
Answer
(C)
3.01 x 1023
22
Consider the following reaction equation:
SO42-(aq) + 2H+(aq) + ye- \(\to\) SO42-(aq) + H2O(1).

The value of y in the equation is
Answer
(A)
2
23
The general gas equation was deprived from______?
Answer
(C)
Boyle's and Charles' laws
24
The vapour pressure of a liquid depends on:
I. Temperature II. rate of condensation III. Cohesive forces holding the particles together.
Answer
(C)
I and III
25
Which of the following gases will diffuse most rapidly?

[H = 1.00, C = 12.0, O = 16.0, S = 32.0, Cl = 35.5]
Answer
(C)
CH4
26
When a reaction is endothermic,
Answer
(C)
Heat content of reactants is less than the heat content of product
27
Which of the following statements about intermolecular distances and cohesive forces between gas is correct? They are
Answer
(D)
Large and negligible
28

The following diagram illustrates the rate curve that was obtained when Mg reacted with excess dilute HCl.

The diagram became horizontal at X because

Answer
(C)
All the Mg has reacted
29
An example of an acid salt is
Answer
(C)
NaHSO4
30
Which of the following oxides can be reduced by hydrogen?
Answer
(D)
Silver oxide
31
Solubility is practically applied in
Answer
(D)
Solvent extraction
32
Which of the following compounds is the least soluble in water?
Answer
(B)
CaSO4
33
A substance which dissolves readily in organic solvent would
Answer
(A)
Be a covalent compound
34
A change in the temperature of a saturated solution disturbs the equilibrium between the
Answer
(C)
Dissolved solute and the undissolved solute
35
Which of the following statements about an electrochemical cell is correct? Oxidation occurs
Answer
(A)
At the anode
36
Consider the following reaction equation:
CuO(s) + H2(g) \(\to\) Cu(s) + H2O(1)

Which substance is oxidized?
Answer
(C)
H2
37
Which of the following metals is the strongest reducing agent?
Answer
(C)
Potassium
38
The complete hydrogenation of benzene gives
Answer
(B)
Cyclohexane
39
A compound has an empirical formular CH2O and molecular mass of 90.

[H = 1.00, C = 12.0, O = 16.0]
Answer
(C)
C3H6O3
40
Which of the following reactions would take place when concentrated sodium hydroxide solution is added to palm oil?
Answer
(D)
Saponification
41
Starch could be converted to glucose by the process of
Answer
(D)
Hydrolysis
42
Which of the following compounds is a secondary alkanol?
Answer
(C)
3-methylpentan-2-ol
43
Which of the following substances is a heavy chemical?
Answer
(D)
Tetraoxosulphate(VI)acid
44
Which of the following process does not take place in domestic water treatment?
Answer
(C)
Neutralization
45
A substance responsible for the sour taste of unripe orange is
Answer
(C)
Alkanoic acid