2005 - JAMB Chemistry Past Questions and Answers - page 1

1
To obtain pure carbon (II) oxide from its mixture with carbon (IV) oxide, the mixture should be
A
passed over heated copper (II) oxide
B
bubbled through water
C
bubbled through concentrated tetroxosulphate (VI) acid
D
bubbled through sodium hydroxide
correct option: d
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2
Which of the following equimolar solutions will have the highest pH?
A
CH3COOHa
B
NaOH
C
HCl
D
NH4OH
correct option: b
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3
Which of the following ions require the largest quantity of electricity for discharge at an electrode?
A
4.0 moles of Cl-
B
3.0 moles of Na+
C
2.5 moles of Cu2+
D
2.0 moles of Al3+
correct option: c
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4
Phenolphthalein in acidic solution is
A
red
B
orange
C
colourless
D
yellow
correct option: c
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5
When iron is exposed to moisture and it rusts, the value of ΔG for the reaction is
A
neutral
B
zero
C
positive
D
negative
correct option: d
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6
In which of the following reactions can the oxidation number of the nitrogen be said to have increased?
A
2NO(g) + O2(g) → 2NO2(g)
B
NO(g) + Cl2(g) → NOCl2(l)
C
FeSO4(aq) + NO(g) → Fe(NO)SO4(s)
D
NO(g) + Br2(l) → NOBr2(l)
correct option: a
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7
2H2 + O22 → H2+O ΔH = -571kJ
In the equation above, how much heat will be liberated if 12.0g of hydrogen is burnt in excess oxygen?
A
-1142 kJ
B
-571 kJ
C
+1142 kJ
D
-1713 kJ
correct option: d
2H2 + O22 → H2+O ΔH = -571kJ
4.0g of Hydrogen burn in air to produce -571 kJ
∴ 12.0s of Hydrogen will burn in air to produce
(12 * -571)/4 = -1713kJ
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8
A concentrated solution containing H+, Cu2+, OH- and Cl- was electrolyzed using platinum electrodes.
The ion that will be discharged at the cathode is
A
Cu2+
B
Cl-
C
H+
D
OH-
correct option: a
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9
When sulphur (IV) oxide is passed into a solution of sodium hydroxide for a long time, it eventually produces a solution of
A
NaHSO4
B
Na2SO3
C
NaHSO3
D
Na2SO4
correct option: b
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10
What is the correct IUPAC name for NO2-?
A
Dioxonitrate (IV) ion
B
Trioxonitrate (III) ion
C
Trioxonitrate (IV) ion
D
Dioxonitrate (II) ion
correct option: d
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