1999 - JAMB Chemistry Past Questions and Answers - page 3
21
2SO2(g) + O2(g) ↔ 2SO3(g). In the chemical reaction above, the substance that will increase the rate of production of sulphur (VI) oxide is
A
manganese (IV) oxide
B
finely divided iron
C
vanadium (V) oxide
D
nickel
correct option: c
Users' Answers & Comments22
N2O4(g) ↔ 2NO2(g). Increase in total pressure of the equilibrium reaction above will
A
produce more of NO2(g) in the mixture
B
convert all of N2O4(g) to NO2(g)
C
have no effect on the concentrations of NO2(g)and N2O4(g)
D
produce more of N2O4(g) in the mixture
correct option: d
Users' Answers & Comments23
What quantity of electricity will liberate 0.125 mole of oxygen molecules during the electrolysis of dilute sodium chloride solution?
[ F = 96 5000 C mol-1 ]
[ F = 96 5000 C mol-1 ]
A
24 125 coulombs
B
48 250 coulombs
C
72 375 coulombs
D
96 500 coulombs
correct option: b
4 Faradays of electricity is required to liberate one mole of oxygen gas
∴ quantity of electricity required
= 0.125 * 4 * 96500 = 48250 coulombs
Users' Answers & Comments∴ quantity of electricity required
= 0.125 * 4 * 96500 = 48250 coulombs
24
X + Y → Z. The rate equation for the chemical reaction above is ((-Δ[x])/Δt) = K[X]2[Y].
The overall order of the reaction is
The overall order of the reaction is
A
0.0
B
1.0
C
2.0
D
3.09
correct option: d
Users' Answers & Comments25
When a current I was passed through an electrolyte solution for 40 minutes, a mass X g of a univalent metal was deposited at the cathode. What mass of the metal will be deposited when a current 2I is passed through the solution for 10 minutes?
A
X/4 g
B
X/2 g
C
2X g
D
4X g
correct option: b
From M = zit
Where M = to the mass of the metal liberated
z = Is the electrochemical equivalent
∴ X g = 1 * 1 * 40 * 60
X g = 2400 I
Let Y represent the new mass
Y = 1*2I * 10 * 60
Y = 1200 I
Y/(X g) = 1200 I/2400 I
Y = X/2 g
Users' Answers & CommentsWhere M = to the mass of the metal liberated
z = Is the electrochemical equivalent
∴ X g = 1 * 1 * 40 * 60
X g = 2400 I
Let Y represent the new mass
Y = 1*2I * 10 * 60
Y = 1200 I
Y/(X g) = 1200 I/2400 I
Y = X/2 g
26
RS(aq) + HF(aq) → RF(s) + HS(aq)
ΔH = -65.7 kj mol(-1).
From the equation above, it can be deduced that
ΔH = -65.7 kj mol(-1).
From the equation above, it can be deduced that
A
the heat content of the reactants is lower than that of the products
B
the heat content of the reactants is higher than that of the products
C
the reaction is slow
D
a large amount of heat is absorbed
correct option: b
Users' Answers & Comments27
Which of the following statement is true of the electrochemical series?
A
Electropositivity of metals increase down the series
B
Electropositivity of non-metals decrease down the series
C
Electronegativity of non-metals decrease down the series
D
Electropositivity of metals decreases down the series
correct option: d
Users' Answers & Comments28
The gas that will form a white precipitate with acidified silver trioxonitrate (v) is
A
NH3
B
SO2
C
CO2
D
HCL
correct option: d
Users' Answers & Comments29
Chlorine, bromine and iodine resemble one another in that they
A
dissolve in alkalis
B
react violently with hydorgen without heating
C
are liquids
D
displace one another from solutiions of their salts
correct option: d
Users' Answers & Comments30
The salt that reacts with dilute hydrochloric acid to produce a pungent smelling gas which decolourizes acidified purple potassium tetraoxomanganate (VII) solution is
A
Na2SO4
B
Na2SO3
C
Na2S
D
Na2CO3
correct option: b
Users' Answers & Comments