UME 1981 CHEMISTRY QUESTIONS
1. An
element X has 127 neutrons and 82 electrons. Its atomic number is A. 209, B.
105, C. 45, D. 82, E. 127
2. When
a bottle of coca-cola is opened, bubbles of gas evolve. The gas is A. hydrogen,
B. Carbon monoxide, C. carbon dioxide, D. sulphur dioxide, E. chlorine
3. Which
of the following is the electronic configuration of sodium? (Atomic number of
Na = 11). A. 1s22s22p63s2, B.1s22p63s23p1,
C. 1s22s22p63s1, D. 1s22s22p63s0,
E. 1s22s22p63p64s1.
4. Methane
is a member of the homologous series called A. Alkenes, B. alcohols, C. esters,
D. alkenes, E. alkynes.
5. When
a glowing splint is inserted in the mouth of a jar containing a gas, the splint
is extinguished. The gas gives a white precipitate when passing into barium
hydroxide. The gas is A. methane, B. hydrogen chloride, C. hydrogen, D.
nitrogen, E. carbon dioxide
6. An
example of a strong electrolyte is A. ethylacetate, B. ethanol, C. glucose, D.
sodium formate, E. formic acid.
7. The
oxidation state of manganese in KMnO4 is A. +1, B. +3, C. +5, D. +7,
E. +2
8. For
iron to trust, there should be present A. oxygen, B. moisture, C. carbondioxide,
D. oxygen & moisture, E. Oxygen, moisture and carbon dioxide.
9. The
mass number of an atom is A. the number of electrons in the atom, B. the number
of protons in the nucleus of the atom, C. the number of neutrons in the nucleus
of the atom, D. the sum of numbers of electrons and protons in the atom, E. the
sum of numbers of protons and neutrons in the nucleus of the atom.
10. Sodium
and potassium belong to the same group of the periodic table. This is because
A. both are metals, B. both are soft and
lighter than water, C. both form cations by losing electrons D. both have
identical electronic configurations, E. both react with water vigorously.
11. In
the reaction of oxygen with hydrogen to produce water, which of the following
statements is true? A. one atom of hydrogen react with two atoms of oxygen to
give one molecule of water, B. two atom of hydrogen react with two atoms of
oxygen to give two molecules of water, C. one molecule of oxygen reacts with
one molecule of hydrogen to give two molecules of water, D. one molecule of
hydrogen reacts with two molecules of oxygen to give three molecules of waters,
E. one molecule of oxygen reacts with two molecules of hydrogen to give two
molecules of water.
12. Oxidation
is the process of A. gain of electrons, B. loss of electrons, C. gain of
hydrogen, D. loss of oxygen, E. addition of an electropositive element of
oxygen
13. The
number of atoms in one mole of a substance is equal to A. the atomic number, B.
the Avogadro number, C. the gas constant, D. the number of neutrons, E. the
number of electrons.
14. Which
of the following statements is NOT true of electrovalent compound? A. they are
solids, B. they do not vaporize easily, C. they usually dissolve in water, D.
the elements forming the compounds normally have their valence electrons in a
shared state, E. they conduct electricity
15. If
concentrated sulphuric acid is added to sugar and warmed gently, the sugar
changes from white to brown and finally to a black mass of carbon. In this
reaction concentrated sulphuric acid is acting as A. a drying agent, B. an
oxidizing agent, C. a dehydrating agent, D. a reducing agent, E. a hydrolyzing
agent
16. In
the reaction C + 2HNO3
CO2 + NO + H2O nitric
acid is acting as A. a reducing agent, B. a nitrating agent, C. an oxidizing
agent, D. a catalytic agent, E. a neutralizing agent.
17. The
brown coloration in the nitric acid prepared in the laboratory can be removed
by A. heating the acid, B. bubbling air through the acid, C. cooling the acid,
D. adding a decolourizing agent, E. adding base.
18. Which
of the following processes takes place during electrolysis? A. positive ions
are discharged at the anode by gaining sufficient electrons to become neutral,
B. negative ions are discharged at the anode by gaining sufficient electrons to
become neutral, C. positive ions are discharged at the anode by losing
sufficient electrons to become neutral, E. nothing happens.
19. In
the preparation of ammonia, which of the following is used as the drying agent?
A. CaO, B. Cacl2, C. Conc. H2SO4, D. P2Os,
E. H3PO4
20. Which
of the following can have an isomer? A. C2H4, B. C4H10,
C. C3H8, D. C2H6, E. C6H6
21. Allotropes
are elements having A. different physical but the same chemical properties, B.
different chemical but the same physical, C. the same chemical and physical
properties, D. different atomic structures, E. the same position in the
periodic table.
22. A
polymerization reaction is one in which A. small molecules form giant, B. atoms
form molecules, C. giant molecules form small molecules, D. molecules form
volatile compounds, E. a molecule rearranges itself.
23. Na2CO3
+ 2HCl
2NaCl +H2O + CO2. Using
the above equation, what volume of carbon dioxide, measured at S.T.P. is
liberated when 53g of sodium carbonate is dissolved in hydrochloric acid? (1
mole of gas occupies 22.4dm3 at STP) (Na = 23, C = 12, O = 16) A.
44.8dm2, B. 11.2dm3, C. 3.0dm3, D. 100.1dm3,
E. 22.4dm3
24. When
sodium nitrate dissolves in water, ∆H is positive. This means that A. the
reaction is catalyzed, B. the reaction is complete, C. the reaction is
exothermic, D. the reaction is endothermic, E. sodium nitrite is highly soluble in water
25. If
an organic compound decolourizes bromine water, the compound is A. saturated,
B. supersaturated, unsaturated, C. unsaturated, D. a solid, E. protonated.
26. When
air is compressed, A. its density decreases, B. it solidifies, C. its
temperature decreases, D. its temperature increases, E. it temperature remains
unchanged
27. Fats
and oils are, A. addition product of long-chain fatty acids and alkali, B.
addition products of long-chain fatty acids
and glycerol, C. condensation products of long-chain fatty acids and
glycerol D. condensation product of formaldehyde and glycerol E. liquids at 20oC
28. Which
of the following statements about phosphorus is NOT correct? A. phosphorus is a
solid mineral, B. phosphorus is obtained by oxidation of phosphates, C.
phosphorus exists in two allotropic forms, D. both forms of phosphorus are
inter-convertible, E. yellow phosphorus ignite when rubbed on a rough surface.
29. If
48,000 coulombs of electricity are required to discharge 0.5 mole of sodium
from a molten sodium chloride mass, then the number of coulombs required to
discharge 2 moles of lead from molten lead(II)chloride is A. 48,000, B. 96,000,
C. 192,000, D. 384,000, E. 576,000
30. 28.8cm3
of nitrogen at 15oC is cooled to 0oC at constant
pressure, the new volume of nitrogen is A. 17.4cm3, B. 14.7cm3,
C. 27.3cm3, D. 31.7cm3, E. 34.7cm3
31. In
an experiment, 5.00g of a metal gave 10.59g of its chloride. In another
experiment, 1.50g of the same metal combined with 1.68g of chlorine. The above
data illustrates A. law of Conservation of Mass, B. law of Definite Proportion,
C. law of Multiple Proportions, D. Gay Lussac’s law, E. Avogadro’s law
32. The
product of the reaction betwein dilute sulphuric acid and sodium thiosulphate
crystals are A. Na2SO4 + SO2 + O2 +
H2O, B. Na2SO3 + SO3 + O2
+ H2O, C. Na2SO4 + SO2 + S + H2O,
D . Na2SO4 + SO3 + S + H2O, E. Na2SO4
+ SO2 + H2O only
33. The
following compounds are given with their corresponding boiling points.
|
Compound
|
Boiling point
|
|
I
|
140C
|
|
II
|
240C
|
|
III
|
00C
|
|
IV
|
1200C
|
|
V
|
-20C
|
From
the above information, indicate which of the following is correct. A. all the
compounds gaseous at 20oC, B. one of the compounds is gaseous at 20oC,
C. three of the compounds are gaseous at 20oC, D. three of the
compounds are gaseous at 20oC, E. none of the compounds is gaseous
at 20oC
34. Which
of the following is NOT a true statement of the Kinetic Theory of Gases? A. the
molecules move at random, B. the size of molecules is negligible ad compared
with the volume of gas, C. the molecular collisions are perfectly elastic, D.
every molecule has the same kinetic, E. the average kinetic energy is
proportional to the absolute temperature of the gas.
35. The
electronic configurations of elements X and Y are X = 2, 8, 6, Y = 2,8,7. The
bond in the compound formed by X and Y
is expected to be A. ionic, B. covalent, C. dative covalent, D. metallic, E.
none of the above.
36. 5cm3
of a saturated solution of sodium chloride at 30oC gave, on careful
evaporation, 1.5g of solid salt. The solubility of sodium chloride at 30oC
is (Na = 23, Cl = 35.5) A. 5.00 mole dm-3, B. 5.67 mole dm-3,
C. 6.00 mole dm-3, D. 6.67 mole dm-3, E. 7.00 mole dm-3
37. In
the extraction of iron, which of the following reactions does NOT take place in
the blast furnace? A. CO2 + C
2CO, B. 2Fe2O3 + 3C
4Fe + 3CO2, C. Fe2O3
+ 3CO
2Fe + 3CO2, D. CaCO3
CaO + CO2, E. CaO + SiO2
CaSiO3
38. Pure
sulphuric acid is a liquid of 1.84 density. What volume of it would be required
to prepare 25cm3 of 0.2M solution?
(H =1, S = 32, O = 16) A. 2.00, B. 2.66, C. 3.00, D. 3.66, E. 4.00
39. What
mass of sodium carbonate is in 500cm3 of 0.1 molar sodium carbonate solution?
(Na = 23, C = 122, O = 16) A. 10.6g, B. 5.3g, C. 500g D. 10g, E. 20g
40. Which
of the following compounds and elements would sublime on exposure to the
atmosphere? A. ice, B. Sulphur, C. phosphorus, D. iodine, E. potassium lodide
41. When
hydrogen sulphide and sulphur dioxide are each passed in turn into a solution
of potassium dichromate, A. both gases change the colour of the solution from
yellow to colourless, B. both gases cause sulphur to be deposited, C. only
hydrogen sulphide decolourizes the solution, D. only sulphur dioxide deposits
sulphur, E. only hydrogen sulphide deposits sulphur.
42. Which
one of the following metals is not normally extracted by chemical reduction
because of its position in the electrochemical series? A. Copper, B. iron, C.
lead, D. potassium, E. zinc
43. If 1
mole aluminum contains 6 x 1023 atoms of aluminum, how many atoms are
contained in 0.9g of aluminum? (Al = 27) A. 1.0 x 1021, B. 6.6 x 1021,
C. 2.0 x 1022, D. 6.0 x 1022, E. 5.4 x 1023
44. 4g
each of aluminum foil and aluminum powder was introduced respectively into
flasks P and Q. flask P was treated with warm bench sodium hydroxide and all
the aluminum dissolved in one hour flask Q was treated with cold sodium
hydroxide and all the aluminum dissolved in 10 minutes. What was responsible
for Q reacting faster than P? A. there were more aluminum atoms in Q and P, B.
the heat given off in P retarded the reaction, C. Q generated more pressure
than P during the reaction, D. P generated more pressure than Q, E. Q has a
greater surface area for the reaction than P
45. The
IUPAC name for
|
CH – CH2
– CH3 is
|
|
CH3
|
|
CH3
|
A. 1-methylpentane,
B. (B) 3-methylbutane, C. 2 methylbutane, D. 1 dimethylpropane, E.
2-methylpentane
46. What
happens when the nitrates of potassium, calcium, zinc and copper are separately
heated? A. all the nitrates will decompose to their respective metals, B. the
nitrates of calcium and potassium will decompose to the nitrites, C. only
copper nitrate decomposes to the metal, D. only the nitrates of zinc and copper will decompose to their oxides, E.
the nitrates of calcium, zinc and copper decompose to their oxides
47. The
scale formation in a kettle used for boiling water is caused by the presence in
water of A. calcium sulphate, B. calcium carbonate, C. calcium hydrogen
carbonate, D. calcium hydroxide, E. magnesium sulphate
48. An
efflorescent compound is a substance that, A. absorbs water from the air without dissolving in it, B. is
capable of giving off coloured luminosity, C. gives out water to the
atmosphere, D. absorbs water from the air without dissolving it, E. gives out
its water of crystallization on heating
49. Which
of the following represents a precipitation reaction? A. H2SO4
+ NaCl
NaHSO4 + HCl, B. Fe + H2SO4
FeSO4 + H2, C. 4HCl +
MnO2
MnCl2 + 2H2) + Cl2,
D. NaSO4 + Pb (NO3)2
PbSO4 + 2NaNO3, E. CuO
+ 2HCl
CuCl2 +
50. The general
formula of an alkyl halide (where X represents the halide) is A. CnH2n
- 2X, B. CnH2n +1X C. CnH2n + 2X
D. CnH2nX E.CnH2n-1
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