Chemistry Past Questions

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4,306 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10
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Past Questions

4,306 questions
Question 1 of 20 4,306 total questions
Question 1261
jamb 2003

Hydrogen can be displaced from a hot alkaline solution by?

AFe
BCu
CCa
DSn
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Question 1262
jamb 2003

Metals of the first transition series have special properties which are different from those of groups I and II elements because they have partially filled

As orbitals
Bp orbitals
Cd orbitals
Df orbitals
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Question 1263
jamb 2003

Chlorine gas is prepared in the laboratory by

Aadding concentrated hydrochloric acid to solid manganese (IV) oxide
Baciding concentrated tetraoxosulphate (VI) acid to solid sodium chloride
Cdropping concentrated hydrochloric acid onto potassium tetraoxomanganate (VI) crystals
Daciding concentrated tetraoxosulphate (VI) acid to hydrochloric acid
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Question 1264
jamb 2003

Which of the following is an electrolyte?

AAlcohol
BSodium acetate solution
CSolid potassium hydroxide
DMercury
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Question 1265
jamb 2003

When sugar is dissolved in tea, the reaction is always accomplished by

Apositive change in entropy
Bnegative entropy change
Cno entropy change
Da minimum entropy change
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Question 1266
jamb 2003

CO(g) + H2O(g) → CO2(g) + H2(g)
From the reaction above, calculate the standard enthalpies of formation if CO2(g), H2O(g) and CO(g) in kJ mol-1 are -394, -242, and -110 respectively.

A-262 kJ mol-1
B-42 kJ mol-1
C+42 kJ mol-1
D+262 kJ mol-1
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Question 1267
jamb 2003

In the electrolysis of a concentrated solution of sodium chloride using electrodes, which of the following ions are discharged at the cathode and anode respectively?

ANa+ and Cl-
BNa+ and OH-
CH+ and OH-
DH+ and Cl-
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Question 1268
jamb 2003

When at equilibrium, which of the reactions below will shift to the right if the pressure is increased and the temperature is kept constant?

A2SO3(g) ↔ 2SO2(g) + O2(g)
B2CO2(g) ↔ 2CO(g) + O2(g)
C2H2(g) + O2(g) ↔ 2H2O(g)
D2NO(g) ↔ N2(g) + O2(g)
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Question 1269
jamb 2003

If y is an oxidizing agent that reacts with a reducing agent, Z, which of the following is correct?

AY increases in oxidation number
BY becomes reduced
CZ loses protons
DZ gains protons
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Question 1270
jamb 2003

Which of the following will change when a catalyst is added to a chemical reaction?

AThe activation energy
BThe potential energy of the reactants
CThe heat of the reaction
Dthe potential energy of the product
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Question 1271
jamb 2003

The commonest feature of reactions at the anode is that

Aelectrons are consumed
Boxidation is involved
Cions are reduced
Delectrode dissolves
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Question 1272
jamb 2003

If an equilibrium reaction has ΔH > 0, the reaction will proceed favourably in the forward direction at

AHigh temperature
BAny temperature
CLow temperature
DMinimum temperature
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Question 1273
jamb 2003

A change in temperature of a saturated solution disturb the equilibrium between the

ADissolved solute and the solvent
BSolvent and undissolved solute
CDissolved solute and undissolved solute
DDissolved solute and the solution
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Question 1274
jamb 2003

When 10g of sodium hydroxide is dissolved in 1000cm\(^3\) of water, the sodium formed is approximately
[Na = 23, H = 1, O = 16]

A0.01 mol dm-3
B0.10 mol dm-3
C0.25 mol dm-3
D0.50 mol dm-3
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Question 1275
jamb 2003

Farmlands affected by crude-oil spillage can be decontaminated by

AAdding acidic solution
BUsing aerobic bacteria
CPouring water on the affected water area
DBurning off the oil from the area
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Question 1276
jamb 2003
What mass of K2CrO4 is required to prepare 250cm3 of 0.020 mol dm3 solution?
[K2CrO4 = 194.2g mol-1]
A0.97g
B9.70g
C19.42g
D97.10g
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Question 1277
jamb 2003

A liquid that will dissolve fat is?

AHydrochloric acid
BCalcium hydroxide
CKerosene
DWater
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Question 1278
jamb 2003

The structural component that makes detergent dissolve more quickly in water than soap is

A-SO3- Na+
B-COO-Na-
C-SO4- Na+
D-COO-K+
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Question 1279
jamb 2003

Which of the following ions is acidic?

AK+
BKNO3-
CS2-
DH3O+
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Question 1280
jamb 2003

A consequence of global warming is?

Aair pollution
Bwater pollution
Cincreased humudity
Dflooding
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