Chemistry Past Questions

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2,505 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10
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Past Questions

2,505 questions
Question 1 of 20 2,505 total questions
Question 811
jamb 1997
2X(aq) + MnO2(s) + 4H+(aq) → X2(g) + Mn2+(aq) + 2H2O.
The reaction above can be used for the laboratory preparation of all halogens except fluorine because it is?
Aa poisionous gas
Ban oxidizing agent
Celectronegative in nature
Dhighly reactive
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Question 812
jamb 1997
Coal gas is made up of carbon (II) oxide, hydrogen and?
Anitrogen
Bair
Cargon
Dmethane
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Question 813
jamb 1997
A compound that will NOT produce oxygen on heating is?
Apotasium dioxonitrate (III)
Blead (IV) oxide
Cpotassium trioxochlorate (V)
Dpotassium trioxonitrate (V)
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Question 814
jamb 1997
mE + nF → pG + qH. In the equation above, the equilibrium constant is given by?
A(E)m(F)n/ (G)n(H)q
B(E)(F) / (G)(H)
C(G)p(H)q / (E)m(F)n
D(G)(H) / (E)(F)
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Question 815
jamb 1997
Oxidation of concentrated hydrochloric acid with manganese (IV) oxide liberates a gas used in the?
Amanufacture of tooth pastes
Btreatment of simple golitre
Cvulcanization of rubber
Dsterilization of water
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Question 816
jamb 1997
One method of driving the position of equilibrium of an endothermic reaction forward is to?
Aincrease temperature at constant pressure
Bdcrease pressure at constant temperature
Ccool down the apparatus with water
Ddecreases temperature at constant pressure
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Question 817
jamb 1997
If the rate law obtained for a given reaction is rate = k(X)n (Y)m, what is the overall order of the reaction?
Anm
Bn/m
Cn + m
Dn - m
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Question 818
jamb 1997

2SO2(g) + O2(g) → 2SO3. In the reaction above, the standard heats of formation of SO2(g) and SO3(g) are -297 KJ mol-1 and -396 kJ/mol respectively. The heat change of the reaction is?

A-99 kJ mol-
B-198 kJ mol-
C+198 kJ mol-
D+683kJ mol-
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Question 819
jamb 1997
2H2S(g) + SO2(g) + H2O(I) → 3S(s) + 3H2O(I)..........(i) 3CuO(s) + 2NH3(g) → 3Cu(s) + 3H2O(I) + N2(g).........(II) In the equations above, the oxidizing agent (I) and the reducing agent in (II) respectively are?
AH2S and NH3
BSO2 and CuO
CSO2 and NH3
DH2S and CuO
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Question 820
jamb 1997
What is the oxidation number of Z in K3ZCl6?
A-3
B+3
C-6
D+6
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Question 821
jamb 1997
How many Faraday of electricity are required to deposit 0.20 mole of nickel, if 0.10 Faraday of electricity deposited 2.98g of nickel during electrolysis of its aqueous solution?

(Ni = 58.7, 1F = 96 500 C mol-)
A0.20
B0.30
C0.40
D0.50
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Question 822
jamb 1997
When platinum electrodes are used during the electrolysis of copper (ll) tetraoxosulphate (lV) solution, the solution gets progressively?
Aacidic
Bbasic
Cneutral
Damphoteric
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Question 823
jamb 1997
Given that 15.00 cm3 of H2
SO4 was required to completely neutralize 25.00 cm3 of 0.125 mol dm-3 NaOH, calculate the molar concentration of the acid solution:
A0.925 mol dm-3
B0.156mol dm-3
C0.104 mol dm-3
D0.023 mol dm-3
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Question 824
jamb 1997

Which of the aqueous solutions with the pH values below will liberate hydrogen when it react with magnesium metals?

A13.0
B7.0
C6.5
D3.0
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Question 825
jamb 1997
The hydroxyl ion concentrated, (OH-), in a solution of sodium hydroxide of pH 10.0 is?
A10-10 mol dm-3
B10-6 mol dm-3
C10-4 mol dm-3
D10-2 mol dm-3
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Question 826
jamb 1997
A saturated solution of AgCl was found to have a concentration of 1.30 x 10-5 mol dm-3. The solubility product of AgCl therefore is?
A1.30 x 10-5 mol2 dm-6
B1.30 x 10-7 mol2 dm-6
C1.69 x 10-10 mol2 dm-6
D2.60 x 10-12 mol2 dm-6
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Question 827
jamb 1997

A major process involved in the softening of hard water is the?

Aconversion of a soluble calcium salt to its trioxoncarbonate (lV)
Bdecomposition of calcium trioxocarbonate (lV)
Cconversion of an insoluble calcium salts to its trioxocarbonate (lV)
Doxidation of calcium atoms to its ions
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Question 828
jamb 1997
Which of the following gases is the most dangerous pollutant?
AHydrogen sulphide
BCarbon (lV) oxide
CSulphur (lV) oxide
DCarbon (ll) oxide
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Question 829
jamb 1997
On recrystallization, 20g of magnesium tetraoxosuphate (IV) forms 41 g of magnesium tetraoxosulphate (IV) crystals, MgSO4. yH2O. The value of y is?

(Mg = 24, S = 32, O = 16, H = 1)
A1
B3
C5
D7
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Question 830
jamb 1997
200 cm3 of air was passed over heated copper in a syringe several times to produce copper (II) oxide.
When cooled, the final volume of air recorded was 158cm3. Estimate the percentage of oxygen in the air?
A31%
B27%
C21%
D19%
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