Practice JAMB-style 2012 Chemistry questions with instant scoring and clear explanations. Prepare for UTME and boost your score today.
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Created by: juanbacan
Which of the following methods can be used to obtain pure water from a mixture of sand, water and methanoic acid?
Neutralization with NaOH followed by filtration
Neutralization with NaOH followed by distillation
Fractional distillation
Filtration followed by distillation
How many atoms are present in 6.0 g of magnesium? [Mg = 24, NA = 6.02 × 1023 mol−1]
1.20 × 1022
2.41 × 1022
1.51 × 1023
3.02 × 1023
50 cm³ of gas was collected over water at 10°C and 765 mmHg. Calculate the volume of the gas at s.t.p. if the saturated vapour pressure of water at 10°C is 5 mmHg.
49.19 cm³
48.87 cm³
48.55 cm³
48.23 cm³
An increase in the pressure exerted on gas at a constant temperature results in
a decrease in the number of effective collisions
a decrease in volume
an increase in the average intermolecular distance
an increase in volume
In the reaction 2H2(g) + O2(g) → 2H2O(g), what volume of hydrogen would be left over when 300 cm³ of oxygen and 1000 cm³ of hydrogen are exploded in a sealed tube?
200 cm³
400 cm³
600 cm³
700 cm³
Which of the following are evidences for the particulate nature of matter?
I. Evaporation
II. Sublimation
III. Diffusion
IV. Brownian motion
I and III only
II and IV only
I, II and III only
I, II, III and IV
If the elements X and Y have atomic numbers 11 and 17 respectively, what type of bond can they form?
Dative
Covalent
Ionic
Metallic
A hydrogen atom which has lost an electron contains
one proton only
one neutron only
one proton and one neutron
one proton, one electron and one neutron
The electronic configuration of Mg2+ is
1s² 2s² 2p6 3s² 3p²
1s² 2s² 2p6 3s²
1s² 2s² 2p6
1s² 2s² 2p4
Group VII elements are
monoatomic
good oxidizing agents
highly electropositive
electron donors
Which of the following is used to study the arrangement of particles in crystal lattices?
Alpha-particles
Beta-particles
Gamma-rays
X-rays
Which of the following shows that air is a mixture?
I. It has varied composition from place to place. II. Its constituents can be separated by physical means. III. It contains unreactive noble gases.
I and II only
II and III only
I and III only
I, II and III
The chemicals used to soften hard water involve the addition of
insoluble sodium compounds forming soluble calcium and magnesium ions
soluble sodium compounds forming soluble calcium and magnesium ions
soluble sodium compounds forming insoluble precipitates of calcium and magnesium ions
insoluble precipitates of calcium and magnesium ions
Chlorination of water for town supply is carried out to
make the water colourless
remove germs from the water
make the water tasteful
remove odour from the water
The solubilities of different solutes in a given solvent can be compared by
plotting their solubility curves on separate axes
plotting their solubility curves on the same axes
plotting some curves on the x-axis and others on the y-axis
plotting their solubility curves on the x-axis only
Potassium trioxochlorate(V) (KClO3) has a solubility of 1.5 mol dm−3 at 45°C. On cooling this solution to 20°C, the solubility becomes 0.5 mol dm−3. What mass of KClO3 crystallized out from 1 dm³ of solution? [K = 39, Cl = 35.5, O = 16]
1.00 g
10.00 g
12.25 g
122.50 g
Which of the following pollutants is associated with brain damage?
Carbon(II) oxide
Radioactive fallout
Biodegradable waste
Sulphur(IV) oxide
Which of the following will produce a solution with pH less than 7 at equivalence point?
HNO3 + NaOH
H2SO4 + KOH
HCl + Mg(OH)2
HNO3 + KOH
The number of hydroxonium ions produced by one molecule of an acid in aqueous solution is its
basicity
acid strength
pH
concentration
During a titration experiment, 0.05 moles of carbon(IV) oxide is liberated. What is the volume of gas liberated at s.t.p.?
22.40 dm³
11.20 dm³
2.24 dm³
1.12 dm³
A major factor considered in selecting a suitable method for preparing a simple salt is its
crystalline form
melting point
reactivity with dilute acids
solubility in water
The oxidation number of boron in NaBH4 is
−3
−1
+1
+3
2Na2O2(s) + 2H2O2(I) → 4NaOH(s) + O2(s). Which substance is oxidized?
2NaO2(s)
NaOH(aq)
H2O(l)
O2(g)
What number of moles of Cu2+ will be deposited by 360 coulombs of electricity? [F = 96500 C mol−1]
5.36 × 10−4 mol
1.87 × 10−3 mol
9.35 × 10−4 mol
3.73 × 10−3 mol
A metal M displaces zinc from ZnCl, solution. This shows that
electrons flow from zinc to M
M is more electropositive than zinc
M is more electronegative than zinc
zinc is more electropositive than M
CO(g) + H2O(g) → CO2(g) + H2(g). Calculate the standard heat change if the standard enthalpies of formation of CO2g, H2O(g) and CO(g) in KJ mol-1 are −394, −242 and −110 kJ mol−1 respectively.
+262 KJ mol−1
−262 KJ mol−1
+42 KJ mol−1
−42 KJ mol−1
An increase in entropy can best be illustrated by
mixing of gases
freezing of water
condensation of vapour
solidifying candle wax
The highest rate of production of carbon(IV) oxide can be achieved using
0.05 mol−3 HCl and 5g powdered CaCO3
0.05 mol−3 HCl and 5g lump CaCO3
0.10 mol−3 HCl and 5g powdered CaCO3
0.025 mol−3 HCl and 5g powdered CaCO3
2HCl(aq) + CaCO3(s) → CaCl2(s) + CO2(g) + H2O(l). From the curves L, M, N, P, which represents the production of CO2 gas as dilute HCl is added?
L
M
N
P
2CO(g) + O2(g) ⇌ 2CO2(g). High pressure will favour the forward reaction because the process
high pressure favours gas formation
the reaction is in dynamic equilibrium
the reaction is exothermic
the process occurs with a decrease in volume
A piece of filter paper moistened with lead (ll) ethanoate solution turns black when the paper is dropped into a gas likely to be
sulphur(VI) oxide
hydrogen chloride
sulphur (VI) oxide
hydrogen sulphide
Which gas has a characteristic pungent smell, turns red litmus paper blue and forms dense white fumes with hydrogen chloride gas?
N2
N2O
Cl2
NH3
Commercial bleaching can be carried out using
sulphur (IV) oxide and ammonia
hydrogen sulphide and chlorine
chlorine and sulphur (IV) oxide
ammonia and chlorine
Mineral acids are usually added to commercial hydrogen peroxide to
oxidize it
decompose it
minimize its decomposition
reduce it to water and oxygen
Which compound will give a brick‑red colour in a non‑luminous Bunsen flame?
LiCl
NaCl
CaCl2
MgCl2
The purest form of iron which contains only about 0.1% carbon is
pig iron
wrought iron
cast iron
iron pyrite
A characteristic shared by zinc and other transition elements is the ability to
have variable oxidation states
form complex ions
act as a catalyst
form coloured ions
Which of the following metals is the least reactive?
Pb
Sn
Hg
Au
Geometric isomerism can exist in
hex‑3‑ene
hexane
prop‑1‑ene
3‑methylbut‑1‑ene
Alkanals can be distinguished from alkanones by reaction with
Sudan III stain
starch iodide paper
lithium tetrahydridoaluminate(III)
Fehling’s solution
The isomers of C3H8O are
1‑propanol and 2‑propanol
1‑propanol and 1‑propanol
2‑propanol and 2‑propanone
2‑propanol and 1‑propanol
Carbohydrates have the general formula Cx(H2O)y. In which of the following pairs is x not equal to y?
glucose and starch
maltose and starch
sucrose and fructose
A compound contains 40.0% C, 6.7% H and 53.3% O. If the molecular mass is 180, its molecular formula is [C = 12, H = 1, O = 16]
CH2O
C3H6O3
C6H6O3
C6H12O6
The alkyne that will give a white precipitate with silver trioxonitrate(V) is
CH3CH2C≡CCH2CH3
CH3C≡CCH2CH2CH3
CH3CH2CH2CH2C≡CH
CH3CH2CH2C≡CCH2CH3
The saponification of an alkanoate to produce soap and alkanol involves
dehydration
esterification
hydrolysis
oxidation
2‑methylpropan‑2‑ol is an example of a
primary alkanol
secondary alkanol
tertiary alkanol
quaternary alkanol
The final oxidation product of alkanol, alkanal and alkanoes is
alkanoic acid
alkanoyl halide
alkanoate
alkanamide
Ethanol reacts with concentrated tetraoxosulphate(VI) acid at a temperature above 170°C to form
ethanone
ethene
ethyne
ethanal
An example of an oxidation–reduction enzyme is
amylase
protease
lipase
dehydrogenase
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