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Chemistry
UTME / JAMB 1989
Organic Chemistry I: Hydrocarbons & Crude Oil
Solution
Three liquids X, Y and Z containing only hydrogen and carbon were burnt on a spoon. X and Y burnt with sooty flames while Z did not. Y is able to discharge the colour of bromine water whereas X and Z cannot. Which of the liquids would be aromatic in nature?
A
X and Z
B
Y
C
X
D
Z
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
Aromatic compounds burn with a yellow sooty flame and they don't decolorise bromine water, since bromine is not electrophilic enough except in the presence of a strong Lewis catalyst.
Source: Myschool Past Questions Archive (Record #27600)
Chemistry
UTME / JAMB 1989
Stoichiometry, Mole Concept & Volumetric Analysis
Diagram
Solution
It can be deduced from the vapour pressure curves above that
Attached Figure / Diagram
A
liqiud 1 has the highest boiling point
B
liquid ll has the highest boiling point
C
liquid lll has the highest boiling point
D
liquid lll has the lowest boiling point
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
Trace the iii curve horizontally and you have over 20^\circC temperature
Source: Myschool Past Questions Archive (Record #31392)
Chemistry
UTME / JAMB 1989
Kinetic Theory of Matter & Gas Laws
Diagram
Which of the curves in the above graph illustrates the behaviour of an ideal gas?
Attached Figure / Diagram
A
W
B
X
C
Y
D
Z
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option C.
Source: Myschool Past Questions Archive (Record #31394)
Chemistry
UTME / JAMB 1989
Chemical Energetics & Thermochemistry
Diagram
Solution
The above diagram gives the potential energy profile of the catalyst and uncatalysed reactions of X(g) + Y(g) → XY(g). Deduce the respective activation energies in KJ of the catalysed and uncatalysed reverse reactions: XY(g) → X(g) + Y(g)
Attached Figure / Diagram
A
300, 500
B
500, 300
C
-300, -500
D
-500, -300
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
Activation energy, E\(_a\) of catalysed reaction is 400 - 100kJ = 300kJ and the activation energy, E\(_a\) of uncatalysed reaction = 600 - 100kJ = 500kJ
or
The catalysed reaction = 100 - 400 = -300
The uncatalysed reverse reaction = 100 - 600 = - 500. From the profile diagram, the forward reaction is an exothermic, \DeltaH = - ve, - (- 300) = 300kJ
Also, since the forward reaction was exothermic, the reverse reaction will be endothermic, which means \DeltaH = + ve . Therefore, uncatalysed reversible reaction will be 500kJ.
Consequently, the correct answer is Option A - 300, 500kJ
Source: Myschool Past Questions Archive (Record #31396)
Chemistry
UTME / JAMB 1989
Water, Solutions & Solubility
Diagram
Solution
If in the graph above 1 dm 3 of a saturated solution of KCL is cooled from 80^\circC, the mass of crystals deposited will be
[K = 39, Cl = 35.5]
Attached Figure / Diagram
A
7.45 g
B
14.90 g
C
74.50 g
D
149.00 g
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
Trace the graph to the y-axis to obtain the solubility of the salt at 80^\circC and at the point where the straight line touches the y-axis, the solubility of the salt at these respective temperatures is 4mol\dm3 and 6mol\dm3
solubility of salt that will crystallize out = 6- 4 = 2mol\dm3
therefore mass of salt deposited = solubility x molar mass of salt
2 x 74.5 = 149.00g
Source: Myschool Past Questions Archive (Record #31397)
Chemistry
UTME / JAMB 1989
Stoichiometry, Mole Concept & Volumetric Analysis
Diagram
Solution
The above graph shows a typical heating curve from the solid phase through the liquid phase to the gaseous phase of a substance. Which part of the curve shows solid and liquid in equilibrium?
Attached Figure / Diagram
A
T
B
U
C
X
D
Y
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
point T shows solid-liquid equilibrium. At this point, the substance been heated has begun to melt but has not completely melted forming a solid liquid mixture.
Source: Myschool Past Questions Archive (Record #31399)
Chemistry
UTME / JAMB 1989
Organic Chemistry I: Hydrocarbons & Crude Oil
Diagram
Use the figure above to answer this question. Which of the following compounds is an isomer of the compound
Attached Figure / Diagram
A
A
B
B
C
C
D
D
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option D.
Source: Myschool Past Questions Archive (Record #31400)
Chemistry
UTME / JAMB 1989
Organic Chemistry I: Hydrocarbons & Crude Oil
Diagram
Solution
Use the figure above to answer this question. Which of the following is NOT an isomer of the compound?
Attached Figure / Diagram
A
A
B
B
C
C
D
D
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
Chemical compounds that have identical chemical formulae but differ in properties and the arrangement of atoms in the molecule are called isomers. Isomers have the same molecular formulas but different structural formulas.
The diagram in the given question is 3-methylpentane (C\(_6\)H\(_{14}\)). As we consider the given options,
Option A is 3-ethylpentane (C\(_7\)H\(_{16}\))
Option B is 3-methylpentane (C\(_6\)H\(_{14}\))
Option C is 2-methylpentane (C\(_6\)H\(_{14}\))
Option D is 2-methylpentane (C\(_6\)H\(_{14}\))
From our analysis, all the options except option A has C\(_7\)H\(_{16}\) which doesn't match with the compound given in the question. Hence, it is not an isomer of the compound with the formula C\(_6\)H\(_{14}\).
Source: Myschool Past Questions Archive (Record #31401)
Chemistry
WAEC / WASSCE 1989
Kinetic Theory of Matter & Gas Laws
Solution
120cm\(^3\) of hydrogen were sparked with 60cm\(^3\) of oxygen at 110\(^o\)C. What was the volume of steam produced? The equation for the reaction is
2H\(_2\)(\(_g\) + O\(_2\)(\(_g\) → 2H\(_2\)O\(_g\)
A
30cm3
B
60cm3
C
90cm3
D
120cm3
E
180cm3
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
According to Gay-Lussac's Law of Combining Volumes, it states that when gases react, their volumes combine in a simple whole-number ratio, provided the temperature and pressure are constant.
Consequently, 2H\(_2\)(\(_g\) + O\(_2\)(\(_g\) → 2H\(_2\)O\(_g\)
2 : 1 : 2
120cm\(^3\): 60cm\(^3\) : 120cm\(^3\)
Hence, 120cm\(^3\) of steam was produced.
Source: Myschool Past Questions Archive (Record #36059)
Chemistry
WAEC / WASSCE 1989
Metals, Transition Elements & Extraction
The earthly impurities in iron ore are removed in the blast furnace by the reaction
A
CO2 + C →2CO
B
Fe2O3 + 3CO →2Fe + 3CO2
C
SiO2 + CaO →CaSiO3
D
CaCO3 → CaO + CO2
E
C +CO2 → CO2
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option C.
Source: Myschool Past Questions Archive (Record #36060)
Chemistry
WAEC / WASSCE 1989
Stoichiometry, Mole Concept & Volumetric Analysis
Which of the following hydrocarbons is not likely to be present in petrol?
A
C14H30
B
C10H22
C
C9H20
D
C7H16
E
C5H12
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option A.
Source: Myschool Past Questions Archive (Record #36061)
Chemistry
WAEC / WASSCE 1989
Nature of Matter & Separation Techniques
The most suitable method to use when separating an insoluble solid from a liquid is
A
evaporation
B
filtration
C
magnetization
D
sublimation
E
distillation
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option B.
Source: Myschool Past Questions Archive (Record #36062)
Chemistry
WAEC / WASSCE 1989
Organic Chemistry II: Functional Groups, Polymers & Biomolecules
The following are miscible with water except
A
ethylethanoate
B
methanol
C
ethanoic acid
D
methanoic acid
E
ethanol
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option A.
Source: Myschool Past Questions Archive (Record #36063)
Chemistry
WAEC / WASSCE 1989
Stoichiometry, Mole Concept & Volumetric Analysis
If 200cm 3 of a gas at s.t.p. has a mass of 0.268g, what is its molar mass? (Molar volume of a gas at s.t.p. = 22.4 dm3)
A
300g
B
200g
C
150g
D
30g
E
15g
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option D.
Source: Myschool Past Questions Archive (Record #36064)
Chemistry
WAEC / WASSCE 1989
Organic Chemistry I: Hydrocarbons & Crude Oil
How many carbon atoms are there in a benzene ring?
A
4
B
5
C
6
D
7
E
8
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option C.
Source: Myschool Past Questions Archive (Record #36065)