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Chemistry
UTME / JAMB 1981
Metals, Transition Elements & Extraction
Solution
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
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
In the extraction of iron in a blast furnace, the reduction of iron(III) oxide (Fe₂O₃) primarily occurs through reaction with carbon monoxide (CO), which is the main reducing agent. While direct reduction with solid carbon (C) can occur to a small extent at very high temperatures, the specific stoichiometry shown in Option B is not a standard or balanced representation of the process occurring in the furnace.
Source: Myschool Past Questions Archive (Record #14030)
Chemistry
UTME / JAMB 1981
Stoichiometry, Mole Concept & Volumetric Analysis
Solution
Pure sulfuric acid is a liquid of 1.84 density. What volume of it would be required to prepare 250 cm3 of 2.0 M solution?
(H = 1, S = 32, O = 16)
A
2.00
B
2.66
C
3.00
D
3.66
E
4.00
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
1000 cm3 of 1 m H2SO4 contains 98 gm of H2SO4
250 of 1 m H2SO4 (98)/(4) x (2)/(10) = 4.9 gm
But density = (mass)/(volume)
Volume = (Mass)/(Density) (4.90)/(1.84) = 2.66
Source: Myschool Past Questions Archive (Record #14033)
Chemistry
UTME / JAMB 1981
Stoichiometry, Mole Concept & Volumetric Analysis
Solution
What mass of sodium carbonate solution is in 500 cm3 of 0.1 molar sodium carbonate solution?
(Na = 23, C = 12, O = 16)
A
10.6 g
B
5.3 g
C
500 g
D
10 g
E
20 g
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
106 gm Na2CO3 in 1000 cc = 1m
53 gm Na2CO3 in 500 cc = 1m
For 0.1 molar we have (53)/(10) = 5.3
Source: Myschool Past Questions Archive (Record #14034)
Chemistry
UTME / JAMB 1981
Stoichiometry, Mole Concept & Volumetric Analysis
Which of the following compounds and elements would sublime on exposure to the atmosphere?
A
Ice
B
Sulphur
C
Phosphurous
D
Iodine
E
Potassium iodie
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 #14035)
Chemistry
UTME / JAMB 1981
Non-Metals & Their Compounds
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 causes sulphur to be deposited
C
only hydrogen sulphide decolourizes the solution
D
only sulphur dioxide deposits sulphur
E
only hydrogen sulphide deposits sulphur
medium Difficulty
Verified Correct Answer: Option E
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option E.
Source: Myschool Past Questions Archive (Record #14036)
Chemistry
UTME / JAMB 1981
Electrolysis & Electrochemical Cells
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
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 #14038)
Chemistry
UTME / JAMB 1981
Stoichiometry, Mole Concept & Volumetric Analysis
Solution
If one mole of aluminium contains 6 x 1023 atoms of aluminium, how many atoms are contained in 0.9g of aluminium?
(Al = 27)
A
1.0 x 1021
B
6.6 x 1021
C
2.0 x 1022
D
1.0 x 1022
E
5.4 x 1023
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
1 Mole or 27 gms of Al contains 6 x 1021 atoms
0.9 gms of Al will contain (6 x 1023 x 0 g)/(27 1) = 0.2 x 1023 or 1022
Source: Myschool Past Questions Archive (Record #14050)
Chemistry
UTME / JAMB 1981
Stoichiometry, Mole Concept & Volumetric Analysis
4g each of aluminium foil and aluminium powder were introduced respectively into flasks P and Q.
Flask P was treated with warm bench sodium hydroxide and all the aluminium dissolved in one hour. Flask Q was treated with cold sodium hydroxide and all the aluminium dissolved in 10 minutes. What was responsible for Q reacting faster than P?
A
There were more aluminium atoms in Q than P
B
The heat given off in 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
medium Difficulty
Verified Correct Answer: Option E
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option E.
Source: Myschool Past Questions Archive (Record #14051)
Chemistry
UTME / JAMB 1981
Stoichiometry, Mole Concept & Volumetric Analysis
Solution
What happens when the nitrates of potassium, calcium, zinc and copper are separately heated?
A
All the nitrate will decompose to their respective metals
B
The nitrates of calcium and potassium will decomposes to their 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
medium Difficulty
Verified Correct Answer: Option E
Chemical Principles & Mechanism
The nitrates of calcium, zinc and copper decompose to their metal oxides
Source: Myschool Past Questions Archive (Record #14053)
Chemistry
UTME / JAMB 1981
Stoichiometry, Mole Concept & Volumetric Analysis
Solution
The scale formation in a kinetic 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
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
The scale is produced when soluble Ca(HCO3)2 breaks down on heating to form insoluble CaCO3
eqn Ca (HCO3)2(aq) -----> CaCO3 (s) + CO2 (g) + H2O (l)
Source: Myschool Past Questions Archive (Record #14054)
Chemistry
UTME / JAMB 1981
Water, Solutions & Solubility
Solution
An efflorescent compound is a substance that?
A
absorbs water froom 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 and dissolves in it
E
gives out its water of crystallization on heating
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
Efflorescence is a phenomenon where a crystalline salt loses all or part of its water of crystallization when exposed to the atmosphere to form a lower dehydrate or an anhydrous salt.
Source: Myschool Past Questions Archive (Record #14055)
Chemistry
UTME / JAMB 1981
Stoichiometry, Mole Concept & Volumetric Analysis
The general formula of an alkyl halide (which represent the halide) is?
A
CnH2n - 2X
B
CnH2n + 1X
C
CnH2n + 2X
D
CnH2nX
E
CnH2n - 1
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 #14059)
Chemistry
UTME / JAMB 1981
Organic Chemistry I: Hydrocarbons & Crude Oil
Diagram
Solution
The IUPAC name for
Attached Figure / Diagram
A
1-methlpentane
B
3-methylbutane
C
2-methylbutane
D
1-dimethylpropane
E
2-methylpentane
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
Firstly, identify the parent name. Since the longest C-C chain is 4, the parent name is Butane.
Secondly, identify the substituent, i.e the other functional group attached to any of the c-c longest chain. We have a methyl group ( CH\(_3\) on C-2, hence the name, 2 - methyl
Thirdly, join the two names together i.e 2-methyl butane.
Source: Myschool Past Questions Archive (Record #31313)
Chemistry
UTME / JAMB 1981
Stoichiometry, Mole Concept & Volumetric Analysis
Which of the following represents a precipitation reaction?
A
H2SO4 + NaCl \(\to\) NaHSO4 + HCl
B
Fe +H2SO4 \(\to\) FeSO4 + H2
C
4HCl + MnO2 \(\to\) MnCl2 + 2H2O + Cl2
D
Na2SO4 + pb(NO3) \(\to\) PbSO4 + 2NaNO
E
CuO +2HCl \(\to\) Cl2 + H2O
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: Official Exam / Past Question Archive
Chemistry
UTME / JAMB 1981
Stoichiometry, Mole Concept & Volumetric Analysis
Which of the following represents a precipitation reaction?
A
H2SO4 + NaCl \(\to\) NaHSO4 + HCl
B
Fe +H2SO4 \(\to\) FeSO4 + H2
C
4HCl + MnO2 \(\to\) MnCl2 + 2H2O + Cl2
D
Na2SO4 + pb(NO3) \(\to\) PbSO4 + 2NaNO
E
CuO +2HCl \(\to\) Cl2 + H2O
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 #44488)