Chemistry Past Questions

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64 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10
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Past Questions

64 questions
Question 1 of 20 64 total questions
Question 21
jamb 1998
A solution containing chloride ions gives white precipitate with silver trioxonitrate(V) Solution. The precipitate will be insoluble in dilute?
AHNO 3 but soluble in ammonia solution
BHNO3 and ammonia solution
CHCl but soluble in ammonia solution
DHCl and in ammonia solution
View Explanation & Discuss
Question 22
jamb 1998
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?
Abasic properties of ammonia
Bacidic properties of ammonia
Creducing properties of ammonia
Doxidizing properties of ammonia
View Explanation & Discuss
Question 23
jamb 1998
A gas that turns a filter paper previously soaked in lead ethanoate solution black is?
Ahyrogen chloride
Bhydrogen sulphide
Csulphur (IV) oxide
Dsulphur (VI) oxide
View Explanation & Discuss
Question 24
jamb 1998

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?

AR = k (X)(Y)
BR = K (X) ° (Y)
CR = K (X) ° (Y) 2
DR = K (X) 2(Y)°
View Explanation & Discuss
Question 25
jamb 1998
2Cl2(g) + 2H2O(g) 4HCl(g) + O2(g)
∆H° = +115KJ mol-1. In the above equilibrium reaction, a decrease in temperature will?
Afavour the reverse reaction
Bfavour the forward reaction
Chave no effect on the equilibrium state
Ddouble the rate of the reverse raection
View Explanation & Discuss
Question 26
jamb 1998
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?
ACu (s)
BCd(s)
CZnsub>(s)
DMg(s)
View Explanation & Discuss
Question 27
jamb 1998

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?

A1.3
B7.0
C9.7
D12.7
View Explanation & Discuss
Question 28
jamb 1998

Soap lather is an example of a colloid in which a?

Aliquid is dispersed in gas
Bsolid is dispersed in liquid
Cgas is dispersed in liquid
Dliquid is despersed in liquid
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Question 29
jamb 1998
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)
A52.0g
B58.5g
C85.5g
D88.5g
View Explanation & Discuss
Question 30
jamb 1998
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?
AyzX + 10n → y - 1z + 1X
ByzX + 10n → y + 1zX
CyzX + 10n → yz + 1X
DyzX + 10n → y + 1z - 1X
View Explanation & Discuss
Question 31
jamb 1998

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?

Acarbon (IV) oxide, nitrogen and the rare gases
Bnitrogen and the rare gases
Ccarbon (IV) oxide, nitrogen (IV) oxide and the rare gases
Dcarbon (IV) oxide
View Explanation & Discuss
Question 32
jamb 1998
The soil around a battery manufacturing factory is likely to contain a high concentration of?
ACa2+ salts
BPb2+ salts
CMg2+ salts
DAl3+ salts
View Explanation & Discuss
Question 33
jamb 1998

Potassium tetraoxomanganate (VII) is often added to impure water to?

Areduce organic impurities
Breduce inorganic impurities
Cdestroy bacteria and algae
Dremove permanent hardness
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Question 34
jamb 1998
The property used in obtaining oxygen and nitrogen industrially from air is the?
Aboiling point
Bdensity
Crate of diffusion
Dsolubility
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Question 35
jamb 1998
The line observed in the sample hydrogen spectrum are due to emission of?
Aelectrons from the atoms
Benergy by proton transition
Cenergy by electron transition
Dneutron from the atom
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Question 36
jamb 1998
Which of the following electron configurations indicates an atom with the highest ionization energy?
A2,8,7
B2,8,8,1
C2,8,8,2
D2,8,8,7
View Explanation & Discuss
Question 37
jamb 1998

A solid begins to melt when?

Aconstituent particles acquires a greater kinetic energy
Benergy of vibration of particles of the solid is less than the intermolecular forces
Cconstituent particles acquires energy above the average kinetic energy
Denergy of vibration of particles of the solid equals the intermolecular forces
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Question 38
jamb 1998
If sulphur (IV) oxide and methane are released simultaneously at the opposite ends of a narrow tube, the rates of diffusion Rso2 and Rch4 will be in the ratio?

(S = 32, O = 16, C = 12, H = 1)
A4:1
B2:1
C1:2
D1:4
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Question 39
jamb 1998
30cm3 of hydrogen was collected over water at 27°C and 780 mm Hg. If the vapour pressure of water at the temperature of the experiment was 10 mm Hg, calculate the volume of the gas at 760 mm Hg and 7°C?
A40.0 cm3
B35.7 cm3
C28.4 cm3
D25.2 cm3
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Question 40
jamb 1998
C3H8(g) + 502(g) → 4H2O + 3CO2(g). Form the equation above the volume of oxygen at s.t.p. required to burn 50cm3 of propane is?
A250 cm3
B150 cm3
C100 cm 3
D50 cm3
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