2003 - JAMB Chemistry Past Questions and Answers - page 3
21
If an equilibrium reaction has ΔH > 0, the reaction will proceed favourably in the forward direction at
A
High temperature
B
Any temperature
C
Low temperature
D
Minimum temperature
correct option: a
Users' Answers & Comments22
The commonest feature of reactions at the anode is that
A
electrons are consumed
B
oxidation is involved
C
ions are reduced
D
electrode dissolves
correct option: b
Users' Answers & Comments23
Which of the following will change when a catalyst is added to a chemical reaction?
A
The activation energy
B
The potential energy of the reactants
C
The heat of the reaction
D
the potential energy of the product
correct option: a
Users' Answers & Comments24
If y is an oxidizing agent that reacts with a reducing agent, Z, which of the following is correct?
A
Y increases in oxidation number
B
Y becomes reduced
C
Z loses protons
D
Z gains protons
correct option: b
Users' Answers & Comments25
When at equilibrium, which of the reactions below will shift to the right if the pressure is increased and the temperature is kept constant?
A
2SO3(g) ↔ 2SO2(g) + O2(g)
B
2CO2(g) ↔ 2CO(g) + O2(g)
C
2H2(g) + O2(g) ↔ 2H2O(g)
D
2NO(g) ↔ N2(g) + O2(g)
correct option: c
Users' Answers & Comments26
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?
A
Na+ and Cl-
B
Na+ and OH-
C
H+ and OH-
D
H+ and Cl-
correct option: d
Users' Answers & Comments27
CO(g) + H2O(g) → CO2(g) + H2(g)
From the reaction above, calculate the standard enthalpies of formation of CO2(g), H2O(g) and CO(g) in kJ mol-1 are -394, -242, and -110 respectively.
From the reaction above, calculate the standard enthalpies of formation of 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
correct option: b
CO + H2O → CO2 + H2 DH = 394 kJ mol-1
-242 + 110 = -352 kJ mol-1
35 = -394 -(352)
= -394 + 352
= -42 kJ mol-1
Users' Answers & Comments-242 + 110 = -352 kJ mol-1
35 = -394 -(352)
= -394 + 352
= -42 kJ mol-1
28
When sugar is dissolved in tea, the reaction is always accomplished by
A
positive change
B
negative entropy change
C
no entropy change
D
a minimum entropy change
correct option: c
Users' Answers & Comments29
Which of the following is an electrolyte?
A
Alcohol
B
Sodium acetate solution
C
Solid potassium hydroxide
D
Mercury
correct option: b
Users' Answers & Comments30
Chlorine gas is prepared in the laboratory by
A
adding concentrated hydrochloric acid to solid manganese (IV) oxide
B
aciding concentrated tetraoxosulphate (VI) acid to solid sodium chloride
C
dropping concentrated hydrochloric acid onto potassium tetraoxomanganate (VI) crystals
D
aciding concentrated tetraoxosulphate (VI) acid to hydrochloric acid
correct option: a
Users' Answers & Comments