Year :
2012
Title :
Chemistry
Exam :
JAMB Exam
Paper 1 | Objectives
21 - 30 of 45 Questions
| # | Question | Ans |
|---|---|---|
| 21. |
A major factor considered in selecting a suitable method for preparing a simple salt is its A. Crystalline from B. melting point C. reactivity with dilute acids D. solubility in water |
|
| 22. |
The oxidation number of boron in NaBH 4 is A. -3 B. -1 C. +1 D. +3 |
|
| 23. |
Na2O2(s) + H2O(1) → NaOH(s) +O2(g) A. 2NaO2(s) B. NaOH(aq) C. H2O(1) D. O2(g) |
|
| 24. |
What number of moles of Cu 2+ will be deposited by 360 coulombs of electricity? A. 5.36 x 10 -4 mole B. 87 x 10 10 -3 mole C. 35 x 10 -4 mole D. 73 x 10 -3 Detailed SolutionCu\(^{2+}\) + 2e\(^{-}\)\(_{(aq)}\) \(\rightarrow\) Cu\(_{(s)}\)Liberating 1 mole of Cu 2 x 1F = 2 x 96,500C = 193,000C of electricity is needed Hence, 193,000C = 1 mole 360C of electricity = \(\frac{360C \times 1 mol}{193,000C}\) = 0.001865 mol = 1.87 x 10\(^{-3}\) moles There is an explanation video available below. |
|
| 25. |
A metal M displaces zinc from ZnCl solution A. electrons flow from zinc to M B. M is more electropositive than zinc C. M is more electonegative than zinc D. zinc is more electropositive than M |
|
| 26. |
CO(g) + H\(_2\) O\(_{(g)}\) → CO\(_{2(g)}\) + H\(_{2(g)}\) A. + 262 KJ mol -1 B. - 262 KJ mol -1 C. + 42 KJ mol -1 D. - 42 KJ mol -1 Detailed Solution\(\Delta H (formation) (CO_2) = -394\)\(\Delta H (formation) (H_2 O) = -242\) \(\Delta H (formation) (CO) = -110\) \(X = \sum H_{P} ^{F} - \sum H_{R} ^{F}\) = (-394+ 0) - (-110 - 242 ) = -394 +352 = - 42 kJmol\(^{-1}\) There is an explanation video available below. |
|
| 27. |
An increase in entropy can best be illustrated by A. mixing of gases B. freezing of water C. the condensation of vapour D. solidifying candle wax |
|
| 28. |
The highest rate of production of carbon (lV) oxide can be achieved using A. 0.05 mol -3HCI and 5g powdered CaCO3 B. 0.05 mol -3HCI and 5g lump CaCO3 C. 0.10 mol -3HCI and 5g powdered CaCO3 D. 0.025 mol -3HCI and 5g powdered CaCO3 |
|
| 29. |
A piece of filter paper moistened with lead (ll) ethanoate solution turns black when the paper is dropped into a gas likely to be A. sulphur (VI) oxide B. hydrogen chloride C. sulphur (VI) oxide D. hydrogen sulphide |
|
| 30. |
Which of the following gases has a characteristic pungent smell, turns red litmus paper blue and forms dense white fumes with hydrogen chloride gas? A. N2 B. N2O C. CI2 D. NH3 |
| 21. |
A major factor considered in selecting a suitable method for preparing a simple salt is its A. Crystalline from B. melting point C. reactivity with dilute acids D. solubility in water |
|
| 22. |
The oxidation number of boron in NaBH 4 is A. -3 B. -1 C. +1 D. +3 |
|
| 23. |
Na2O2(s) + H2O(1) → NaOH(s) +O2(g) A. 2NaO2(s) B. NaOH(aq) C. H2O(1) D. O2(g) |
|
| 24. |
What number of moles of Cu 2+ will be deposited by 360 coulombs of electricity? A. 5.36 x 10 -4 mole B. 87 x 10 10 -3 mole C. 35 x 10 -4 mole D. 73 x 10 -3 Detailed SolutionCu\(^{2+}\) + 2e\(^{-}\)\(_{(aq)}\) \(\rightarrow\) Cu\(_{(s)}\)Liberating 1 mole of Cu 2 x 1F = 2 x 96,500C = 193,000C of electricity is needed Hence, 193,000C = 1 mole 360C of electricity = \(\frac{360C \times 1 mol}{193,000C}\) = 0.001865 mol = 1.87 x 10\(^{-3}\) moles There is an explanation video available below. |
|
| 25. |
A metal M displaces zinc from ZnCl solution A. electrons flow from zinc to M B. M is more electropositive than zinc C. M is more electonegative than zinc D. zinc is more electropositive than M |
| 26. |
CO(g) + H\(_2\) O\(_{(g)}\) → CO\(_{2(g)}\) + H\(_{2(g)}\) A. + 262 KJ mol -1 B. - 262 KJ mol -1 C. + 42 KJ mol -1 D. - 42 KJ mol -1 Detailed Solution\(\Delta H (formation) (CO_2) = -394\)\(\Delta H (formation) (H_2 O) = -242\) \(\Delta H (formation) (CO) = -110\) \(X = \sum H_{P} ^{F} - \sum H_{R} ^{F}\) = (-394+ 0) - (-110 - 242 ) = -394 +352 = - 42 kJmol\(^{-1}\) There is an explanation video available below. |
|
| 27. |
An increase in entropy can best be illustrated by A. mixing of gases B. freezing of water C. the condensation of vapour D. solidifying candle wax |
|
| 28. |
The highest rate of production of carbon (lV) oxide can be achieved using A. 0.05 mol -3HCI and 5g powdered CaCO3 B. 0.05 mol -3HCI and 5g lump CaCO3 C. 0.10 mol -3HCI and 5g powdered CaCO3 D. 0.025 mol -3HCI and 5g powdered CaCO3 |
|
| 29. |
A piece of filter paper moistened with lead (ll) ethanoate solution turns black when the paper is dropped into a gas likely to be A. sulphur (VI) oxide B. hydrogen chloride C. sulphur (VI) oxide D. hydrogen sulphide |
|
| 30. |
Which of the following gases has a characteristic pungent smell, turns red litmus paper blue and forms dense white fumes with hydrogen chloride gas? A. N2 B. N2O C. CI2 D. NH3 |