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Chemistry WAEC / WASSCE 1997 Atomic Structure, Orbitals & Nuclear Chemistry
A sodium atom and a sodium ion have the same
A
number of neutrons
B
number of electrons
C
electric charge
D
electronic structure
E
chemical properties
medium Difficulty
Chemistry WAEC / WASSCE 1997 Atomic Structure, Orbitals & Nuclear Chemistry
If the atomic number of an element X is 11 and that of nitrogen is 7, the most likely formula of the nitride of X is
A
X3N
B
XN3
C
X3N2
D
N2X
E
NX2
medium Difficulty
Chemistry WAEC / WASSCE 1997 Particulate Nature of Matter, Laws & Formulae
An increase in the pressure of a gas results in a decrease in its
A
mass
B
vapour density
C
volume
D
temperature
E
concentration
medium Difficulty
Chemistry WAEC / WASSCE 1997 Organic Chemistry I: Hydrocarbons & Crude Oil
A given volume of methane diffuses in 20 seconds. How long will it take the same volume of sulphur (IV) oxide to diffuse under the same conditions? [CH\(_4\) = 16; SO\(_2\) = 64]
A
5 seconds
B
20 seconds
C
40 seconds
D
60 seconds
E
80 seconds
medium Difficulty
Chemistry WAEC / WASSCE 1997 Stoichiometry, Mole Concept & Volumetric Analysis
An acid is a substance which in the presence of water produces
A
salts
B
oxygen
C
effervescence
D
hydroxonium ions
E
hydrogen gas
medium Difficulty
Chemistry WAEC / WASSCE 1997 Water, Solutions & Solubility
The loss of molecules of water of crystallization to the atmosphere by some crystalline salts is known as
A
efflorescence
B
effervescence
C
phosphorescence
D
fluorescence
E
deliquescence
medium Difficulty
Chemistry WAEC / WASSCE 1997 Electrolysis & Electrochemical Cells
Which of the following ions will migrate to the cathode during electrolysis?
A
Zinc ions
B
Chloride ions
C
Sulphide ions
D
Tetraoxosulphate (Vl) ions
E
Trioxonitrate (V) ions
medium Difficulty
Chemistry WAEC / WASSCE 1997 Stoichiometry, Mole Concept & Volumetric Analysis
What quantity of electrons (in mole) is lost when one mole of iron (ll) ions is oxidized to iron (lll) ions?
A
5 mole
B
4 mole
C
3 mole
D
2 mole
E
1 mole
medium Difficulty
Chemistry WAEC / WASSCE 1997 Electrolysis & Electrochemical Cells
The common feature of reactions at the anode is that
A
electrons are consumed
B
oxidation is involved
C
ions are reduced
D
the electrode dissolves
E
the electrolyte is diluted
medium Difficulty
Chemistry WAEC / WASSCE 1997 Stoichiometry, Mole Concept & Volumetric Analysis
From the following equations, what is the order of decreasing reactivity of X, Y and Z? Y (s) + X2+(aq) → Y2+(aq) + X(s) X(s) + Z2+(aq) → X2+(aq) + Z(s)
A
X>Y>Z
B
Y > X > Z
C
Z > Y > X
D
Y > Z > X
E
X > Z > Y
medium Difficulty
Chemistry WAEC / WASSCE 1997 Oxidation, Reduction & Redox Reactions
What is the value of x in the following equation? MnO- 4 + 4H+ + xe- → MnO 2 + 2H2O
A
2
B
3
C
4
D
7
E
8
medium Difficulty
Chemistry WAEC / WASSCE 1997 Chemical Energetics & Thermochemistry
If the value of ∆H for a reaction is negative, it means that the reaction is
A
slow
B
exothermic
C
spontaneous
D
irreversible
E
not feasible
medium Difficulty
Chemistry WAEC / WASSCE 1997 Stoichiometry, Mole Concept & Volumetric Analysis
How much heat will be liberated if 8g of hydrogen burns in excess oxygen according to the following equation? 2H2 + O2→ 2H2O,∆H = -571.7KJ (H = 1)
A
1.42.9KJ
B
571.7KJ
C
1143.4KJ
D
285.9KJ
E
2286.8KJ
medium Difficulty
Chemistry WAEC / WASSCE 1997 Reaction Rates & Chemical Equilibrium
The position of equilibrium in a reversible reaction is affected by
A
particle size of the reactants
B
change in concentration of the reactants
C
change in size of the reaction vessel
D
vigorous stirring of the reaction mixture
E
presence of a catalyst
medium Difficulty
Chemistry WAEC / WASSCE 1997 Stoichiometry, Mole Concept & Volumetric Analysis
Separation of mixture of solids by physical methods can be based on differences in the following except
A
melting point
B
solubility
C
particle size
D
molar mass
E
magnetic property
medium Difficulty
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