Year :
1992
Title :
Chemistry
Exam :
JAMB Exam
Paper 1 | Objectives
21 - 30 of 51 Questions
| # | Question | Ans |
|---|---|---|
| 21. |
Calculate the mass, in kilograms, of magnesium produced by the electrolysis of magnesium (II) chloride in a cell operating for 24 hours at 500 amperes. A. 2.7 B. 5.4 C. 10.8 D. 21.7 Detailed SolutionMg + 2e → 24 gms2f → 24 gms 2 x 96,500 → 24 gms Q = (500 x 1440 x 60) Q = 4320000 C 1 mole of mg = (1) / (2 x 96,500) x (43200000) / (1) = (24)/(1) = (1036800000) / (193000) = 5372.020725 gms in leg = (5372.020725) / (1000) = 5.4 leg |
|
| 22. |
S2O2-3 + I2 → S2O62- + 2I-. In reaction above, the oxidizing agent is? A. S2O32- B. I2 C. S4O62- D. I- |
B |
| 23. |
MnO2 + 2CI- + 4H+ → MnO2+ + CI2 + 2H2O. A. 2, 2, 4 B. -1, -2, 4 C. -2, 1, 0 D. 2, 4, 0 |
C |
| 24. |
In which of the following is the entropy change positive? A. H2O(I) → H2O(g) B. Cu2+(aq) + Fe(s) → Fe(2+) + Cu(s) C. N2(g) + 3H2(g) → 2NH3(g) D. 2HCI(s) → H2(g) + CI2(g) |
A |
| 25. |
In what way is equilibrium constant for the forward reaction related to that of the reversed reaction? A. The additional of the two is expected to be one B. The product of the two is expected to be one C. The two equilibrium constants are identical D. The product of the two is always greater than one |
A |
| 26. |
Which of the following equilibria shows little or no net reaction when the volume of the system is decreased? A. H2(g) + I2(g) ≈ 2HI(g) B. 2NO2(g) ≈ N2O4(g)O4(g)N2O4(g) C. PCI5(g) ≈ PCI3(g) + CI2(g) D. ZnO(s) + CO2(g) ≈ ZnCO3(g) |
D |
| 27. |
For a general equation of the nature xP + yQ ≈ mR + nS, the expression for the equilibrium constant is? A. k (p)x (Q)y B. (p)x (Q)y / (R)m (S)n C. (R)m (S)n / (p)x (Q)y D. m(R) n (S) / x(P) y (Q) |
C |
| 28. |
Which of these statements is TRUE about carbon (IV) oxide? A. it supports combustion B. It is strongly acidic in water C. It is very soluble in water D. It supports the buring of magnesium to produce magnesium oxide Detailed SolutionCarbon(iv)oxide does not burn, nor support the combustion of most substance .The intense heat produced by burning magnesium, However, decomposes Carbon(iv)oxide to release oxygen for the further oxidation of magnesium. Carbon(iv)oxide dissolves in water to form trioxocarbonate(iv) acid ( soda water). |
|
| 29. |
Which of the following combination of gases is used for metal welding? i. Oxygen and ethyne, ii. Hydrogen and ethyne, iii. Hydrogen and oxygen, iv. Ethyne, hydrogen and oxygen. A. i and ii B. ii and iv C. i and iii D. ii and iv |
A |
| 30. |
Which of the following oxides of nitrogen is unstable in air? A. NO2 B. NO C. N2O4 D. N2O5- |
B |
| 21. |
Calculate the mass, in kilograms, of magnesium produced by the electrolysis of magnesium (II) chloride in a cell operating for 24 hours at 500 amperes. A. 2.7 B. 5.4 C. 10.8 D. 21.7 Detailed SolutionMg + 2e → 24 gms2f → 24 gms 2 x 96,500 → 24 gms Q = (500 x 1440 x 60) Q = 4320000 C 1 mole of mg = (1) / (2 x 96,500) x (43200000) / (1) = (24)/(1) = (1036800000) / (193000) = 5372.020725 gms in leg = (5372.020725) / (1000) = 5.4 leg |
|
| 22. |
S2O2-3 + I2 → S2O62- + 2I-. In reaction above, the oxidizing agent is? A. S2O32- B. I2 C. S4O62- D. I- |
B |
| 23. |
MnO2 + 2CI- + 4H+ → MnO2+ + CI2 + 2H2O. A. 2, 2, 4 B. -1, -2, 4 C. -2, 1, 0 D. 2, 4, 0 |
C |
| 24. |
In which of the following is the entropy change positive? A. H2O(I) → H2O(g) B. Cu2+(aq) + Fe(s) → Fe(2+) + Cu(s) C. N2(g) + 3H2(g) → 2NH3(g) D. 2HCI(s) → H2(g) + CI2(g) |
A |
| 25. |
In what way is equilibrium constant for the forward reaction related to that of the reversed reaction? A. The additional of the two is expected to be one B. The product of the two is expected to be one C. The two equilibrium constants are identical D. The product of the two is always greater than one |
A |
| 26. |
Which of the following equilibria shows little or no net reaction when the volume of the system is decreased? A. H2(g) + I2(g) ≈ 2HI(g) B. 2NO2(g) ≈ N2O4(g)O4(g)N2O4(g) C. PCI5(g) ≈ PCI3(g) + CI2(g) D. ZnO(s) + CO2(g) ≈ ZnCO3(g) |
D |
| 27. |
For a general equation of the nature xP + yQ ≈ mR + nS, the expression for the equilibrium constant is? A. k (p)x (Q)y B. (p)x (Q)y / (R)m (S)n C. (R)m (S)n / (p)x (Q)y D. m(R) n (S) / x(P) y (Q) |
C |
| 28. |
Which of these statements is TRUE about carbon (IV) oxide? A. it supports combustion B. It is strongly acidic in water C. It is very soluble in water D. It supports the buring of magnesium to produce magnesium oxide Detailed SolutionCarbon(iv)oxide does not burn, nor support the combustion of most substance .The intense heat produced by burning magnesium, However, decomposes Carbon(iv)oxide to release oxygen for the further oxidation of magnesium. Carbon(iv)oxide dissolves in water to form trioxocarbonate(iv) acid ( soda water). |
|
| 29. |
Which of the following combination of gases is used for metal welding? i. Oxygen and ethyne, ii. Hydrogen and ethyne, iii. Hydrogen and oxygen, iv. Ethyne, hydrogen and oxygen. A. i and ii B. ii and iv C. i and iii D. ii and iv |
A |
| 30. |
Which of the following oxides of nitrogen is unstable in air? A. NO2 B. NO C. N2O4 D. N2O5- |
B |