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Chemistry
UTME / JAMB 1998
Kinetic Theory of Matter & Gas Laws
The property used in obtaining oxygen and nitrogen industrially from air is the?
A
boiling point
B
density
C
rate of diffusion
D
solubility
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 #13874)
Chemistry
UTME / JAMB 1998
Oxidation, Reduction & Redox Reactions
Solution
Potassium tetraoxomanganate (VII) is often added to impure water to?
A
reduce organic impurities
B
reduce inorganic impurities
C
destroy bacteria and algae
D
remove permanent hardness
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
Potassium permanganate is a point-of-entry treatment method that oxidizes dissolved iron, manganese, and hydrogen sulfide into solid particles that are filtered out of the water. It can also be used to control iron bacteria growth in wells.
Source: Myschool Past Questions Archive (Record #13875)
Chemistry
UTME / JAMB 1998
Stoichiometry, Mole Concept & Volumetric Analysis
The soil around a battery manufacturing factory is likely to contain a high concentration of?
A
Ca2+ salts
B
Pb2+ salts
C
Mg2+ salts
D
Al3+ salts
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 #13877)
Chemistry
UTME / JAMB 1998
Stoichiometry, Mole Concept & Volumetric Analysis
Solution
Excess phosphorus was burnt in a gas jar and the residual gas passed successively over concentrated KOH solution and concentration H2SO4 before being collected in a flask. The gases collected are?
A
carbon (IV) oxide, nitrogen and the rare gases
B
nitrogen and the rare gases
C
carbon (IV) oxide, nitrogen (IV) oxide and the rare gases
D
carbon (IV) oxide
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
So phosphorus will remove oxygen by forming P205, KOH will absorb water vapors, and sulfuric acid will react with carbon dioxide thus removing it from the mixture. So nitrogen and rare gases will be left
Source: Myschool Past Questions Archive (Record #13878)
Chemistry
UTME / JAMB 1998
Atomic Structure, Orbitals & Nuclear Chemistry
If an element X of an atomic number Z and mass number Y is irradiated by an intense concentration of neutrons, the relevant nuclear equation is?
A
yzX + 10n → y - 1z + 1X
B
yzX + 10n → y + 1zX
C
yzX + 10n → yz + 1X
D
yzX + 10n → y + 1z - 1X
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 #13886)
Chemistry
UTME / JAMB 1998
Water, Solutions & Solubility
Solution
90.0g of MgCI2 was placed in 50.0cm3 of water to give a saturated solubility of the salt is 8.0 mol dm3 at the same temperature, what is the mass of the salt left undissolved at the given temperature?
(Mg = 24, Cl = 35.5)
A
52.0g
B
58.5g
C
85.5g
D
88.5g
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
Molar mass of MgCl2 = 95g
The solubility of MgCl2 is 8.0/dm3
1 dm3 = 1000cm3
Solubility of g/cm3
8 x 95 → 1000cm3
x → 50
x = (50)/(1000) x (8 x 95) / (1) = 38g
Mass of the salt left undissolved = 90 - 38 = 52.0g
Source: Myschool Past Questions Archive (Record #13894)
Chemistry
UTME / JAMB 1998
Organic Chemistry II: Functional Groups, Polymers & Biomolecules
Solution
Soap lather is an example of a colloid in which a?
A
liquid is dispersed in gas
B
solid is dispersed in liquid
C
gas is dispersed in liquid
D
liquid is despersed in liquid
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
When soap forms lather, a gas (primarily air) is dispersed within the liquid (soap and water mixture). This creates a frothy, bubbly substance, a foam. The gas is trapped within the bubbles formed by the soap molecules binding to water.
Source: Myschool Past Questions Archive (Record #13905)
Chemistry
UTME / JAMB 1998
Acids, Bases, pH & Salts
Solution
The pH of a solution obtained by mixing 100cm\(^3\) of a 0.1M HCl solution with 100cm\(^3\) of a 0.2M solution of NaOH is?
A
1.3
B
7.0
C
9.7
D
12.7
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
Calculate Moles of Reactants:
Moles of HCl = Molarity x Volume in dm\(^3\) = 0.1 M x 0.1 dm\(^3\) = 0.01 moles
Moles of NaOH = Molarity x Volume in dm\(^3\) = 0.2 M x 0.1dm\(^3\) = 0.02 moles
Determine the Excess Reagent:
The neutralization reaction is a 1:1 ratio: HCl + NaOH → NaCl + H\(_2\)O
Excess NaOH = 0.02 - 0.01 = 0.01 mole
Calculate the Hydroxide Ion Concentration[OH\(^-\)]
Total Volume of the mixture = 100 cm\(^3\) + 100cm\(^3\) = 200 cm\(^3\) = 0.2dm\(^3\)
[OH\(^-\)] = \(\frac{0.01}{0.2}\) = 0.05M
Calculate pOH and pH
pOH = - Log[OH\(^-\)] = - Log[0.05]
= 1.3
But pOH + pH = 14
1.3 + pH = 14
pH = 14 - 1.3
= 12.7
Source: Myschool Past Questions Archive (Record #13907)
Chemistry
UTME / JAMB 1998
Oxidation, Reduction & Redox Reactions
Mg2+(aq) + 2e->(aq) → Mg(s)E°(volts) = 2.370
Zn2+(aq) + 2e->(aq) → Zn(s)E°(volts) = -0.763
Cds2+(aq) + 2e->(aq) → Cd(s)E°(volts) = 0.403
Cu2+(aq) + 2e->(aq) → Cu(s)E°(volts) = 0.340
In the electrochemical series above, the strongest reducing agents is?
A
Cu (s)
B
Cd(s)
C
Znsub>(s)
D
Mg(s)
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 #13908)
Chemistry
UTME / JAMB 1998
Stoichiometry, Mole Concept & Volumetric Analysis
2Cl2(g) + 2H2O(g) 4HCl(g) + O2(g)
∆H° = +115KJ mol-1. In the above equilibrium reaction, a decrease in temperature will?
A
favour the reverse reaction
B
favour the forward reaction
C
have no effect on the equilibrium state
D
double the rate of the reverse raection
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 #13910)
Chemistry
UTME / JAMB 1998
Stoichiometry, Mole Concept & Volumetric Analysis
Solution
2X(g) + Y(g) → Z(g): In the equation above, The rate of formation of Z is found to be independent of the concentration of Y and to quadruple when the concentration of X is doubled. The correct equation for the reaction is?
A
R = k (X)(Y)
B
R = K (X) ° (Y)
C
R = K (X) ° (Y) 2
D
R = K (X) 2(Y)°
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
The problem states that the rate of formation of Z is independent of the concentration of Y. In chemical kinetics, if the rate does not change when the concentration of a reactant changes, the reaction is zero-order with respect to that reactant.
Order with respect to Y = 0. Mathematically, R ∝ [Y]\(^0\)
The problem also states that the rate quadruples (increases by a factor of 4) when the concentration of X is doubled. We can use the general rate proportion
Rate ∝ [Y]\(^n\)
When concentration is 2 [X], the rate is 4 R\(_1\),
This confirms the reaction is second-order with respect to X.
By combining the orders for both reactants, we get the overall rate equation: R = K [X]\(^2\)[Y]\(^0\)
Source: Myschool Past Questions Archive (Record #13911)
Chemistry
UTME / JAMB 1998
Non-Metals & Their Compounds
A gas that turns a filter paper previously soaked in lead ethanoate solution black is?
A
hyrogen chloride
B
hydrogen sulphide
C
sulphur (IV) oxide
D
sulphur (VI) oxide
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 #13914)
Chemistry
UTME / JAMB 1998
Oxidation, Reduction & Redox Reactions
3CuO(s) + 2NH3(g) → 3Cu(s) + 3H2O(I) N2(g) (i).
2NH3(g) + 3Cl2(g) → 6HCl(g) + N2(g) (ii).
4NH3(g) + 3O2(g) → 6H2O(I) + 2N2(g) (iii).
The reactions represented by the equations above demonstrate the?
A
basic properties of ammonia
B
acidic properties of ammonia
C
reducing properties of ammonia
D
oxidizing properties of ammonia
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 #13915)
Chemistry
UTME / JAMB 1998
Stoichiometry, Mole Concept & Volumetric Analysis
A solution containing chloride ions gives white precipitate with silver trioxonitrate(V) Solution. The precipitate will be insoluble in dilute?
A
HNO 3 but soluble in ammonia solution
B
HNO3 and ammonia solution
C
HCl but soluble in ammonia solution
D
HCl and in ammonia solution
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 #13920)
Chemistry
UTME / JAMB 1998
Metals, Transition Elements & Extraction
Solution
Which of the following is observed when a solution of iron (III) chloride is mixed with a solution of sodium hydroxide?
A
A gas is evolved
B
A deep blue precipitate is formed
C
The resultant solution turns green turns
D
A brown precipitate is formed
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
iron(III) chloride is a yellow solution
sodium hydroxide is colourless
iron(III) hydroxide is a reddish brown precipitate
sodium chloride is colourless
So in the reaction, yellow solution when added to sodium hydroxide forms reddish brown precipitate that is insoluble in excess sodium hydroxide.
Source: Myschool Past Questions Archive (Record #13923)