Year :
2012
Title :
Chemistry
Exam :
WASSCE/WAEC MAY/JUNE
Paper 1 | Objectives
21 - 30 of 44 Questions
| # | Question | Ans |
|---|---|---|
| 21. |
Which of the following metals would readily displace hydrogen from steam? A. Copper B. Lead C. Magnesium D. Silver Detailed SolutionIn the electrochemical series, H\(^+\) is above all the other elements in the series except Magnesium. Hence, only Mg\(^{2+}\) can displace hydrogen from a reaction. |
|
| 22. |
The volume occupied by 0.4 g of hydrogen gas at s.t.p. is [H = 1. 00; Molar volume at s.t.p. = 22.4 dm3] A. 2.24 dm3 B. 4.48dm3 C. 22.4dm3 D. 44.8dm 3 Detailed Solution2g of H\(_2\) = 22.4 dm\(^3\)0.4g of H\(_2\) = x, x = \(\frac{0.4 \times 22.4}{2}\) = 4.48dm\(^3\) |
|
| 23. |
When a substance changes directly from the solid state to the gaseous state without forming a liquid, the substance is said to A. condense B. evaporate C. sublime D. precipitate |
C |
| 24. |
At ordinary temperature H\(_2\)O is a liquid while H\(_2\)S is a gas. This is because H\(_2\)O has A. weak intermolecular forces holding its molecules together B. strong hydrogen bonds holding its molecules together C. induced dipole-induced dipole forces between its molecules D. ionic force between its molecules Detailed SolutionH\(_2\)O has stronger intermolecular dipole--dipole interaction because of the greater polarity (or a hydrogen bond). Because of the stronger intermolecular interaction H\(_2\)O is more stable and exists as a liquid. |
|
| 25. |
The postulate that molecules are in constant random motion best explains why liquids A. can undergo solidification B. maintain their volumes C. are incompressible D. have no characteristic shape |
A |
| 26. |
Which of the following gases has the lowest rate of diffusion under the same condition? [H = 1.00; He = 4. 00; O = 16.0; CI = 35.5] A. CI2 B. H2 C. He D. O2 Detailed SolutionAccording to Graham's law of diffusion and effusion,r \(\propto\) \(\sqrt{\frac{1}{M}}\). Therefore, the more the molar mass, the less the rate of diffusion and effusion. |
|
| 27. |
The energy evolved when magnesium burns in air is in the form of A. heat B. heat and sound C. light and heat D. sound Detailed SolutionWhen a piece of magnesium ribbon is ignited, light and heat are produced.The reaction is an exothermic reaction, as well as one that produces light energy. |
|
| 28. |
A substance L reacts with NH\(_4\)NO\(_{3(aq)}\) to generate ammonia gas. L is likely to be A. HCl B. NaOH C. CH3COOH D. CaSO4 Detailed SolutionThe reaction between NH\(_4\)NO\(_{3(aq)}\) and any metal hydroxide produces ammonia, water and an alkali metal nitrate. |
|
| 29. |
On heating, the following trioxocarbonate (IV) salts decompose to give solid residue except A. ammonium trioxocarbonate (IV) B. calcium trioxocarbonate (IV) C. lead (ll) trioxocarbonate(IV) D. zinc trioxocarbonate (IV) Detailed SolutionAmmonium trioxocarbonate (IV) is an unstable compound. It decomposes on heating to yield ammonia, carbon (IV) oxide and water. All of these are gases. |
|
| 30. |
Which of the following pH values indicates that a solution is a strong base? A. 1 B. 5 C. 9 D. 13 |
D |
| 21. |
Which of the following metals would readily displace hydrogen from steam? A. Copper B. Lead C. Magnesium D. Silver Detailed SolutionIn the electrochemical series, H\(^+\) is above all the other elements in the series except Magnesium. Hence, only Mg\(^{2+}\) can displace hydrogen from a reaction. |
|
| 22. |
The volume occupied by 0.4 g of hydrogen gas at s.t.p. is [H = 1. 00; Molar volume at s.t.p. = 22.4 dm3] A. 2.24 dm3 B. 4.48dm3 C. 22.4dm3 D. 44.8dm 3 Detailed Solution2g of H\(_2\) = 22.4 dm\(^3\)0.4g of H\(_2\) = x, x = \(\frac{0.4 \times 22.4}{2}\) = 4.48dm\(^3\) |
|
| 23. |
When a substance changes directly from the solid state to the gaseous state without forming a liquid, the substance is said to A. condense B. evaporate C. sublime D. precipitate |
C |
| 24. |
At ordinary temperature H\(_2\)O is a liquid while H\(_2\)S is a gas. This is because H\(_2\)O has A. weak intermolecular forces holding its molecules together B. strong hydrogen bonds holding its molecules together C. induced dipole-induced dipole forces between its molecules D. ionic force between its molecules Detailed SolutionH\(_2\)O has stronger intermolecular dipole--dipole interaction because of the greater polarity (or a hydrogen bond). Because of the stronger intermolecular interaction H\(_2\)O is more stable and exists as a liquid. |
|
| 25. |
The postulate that molecules are in constant random motion best explains why liquids A. can undergo solidification B. maintain their volumes C. are incompressible D. have no characteristic shape |
A |
| 26. |
Which of the following gases has the lowest rate of diffusion under the same condition? [H = 1.00; He = 4. 00; O = 16.0; CI = 35.5] A. CI2 B. H2 C. He D. O2 Detailed SolutionAccording to Graham's law of diffusion and effusion,r \(\propto\) \(\sqrt{\frac{1}{M}}\). Therefore, the more the molar mass, the less the rate of diffusion and effusion. |
|
| 27. |
The energy evolved when magnesium burns in air is in the form of A. heat B. heat and sound C. light and heat D. sound Detailed SolutionWhen a piece of magnesium ribbon is ignited, light and heat are produced.The reaction is an exothermic reaction, as well as one that produces light energy. |
|
| 28. |
A substance L reacts with NH\(_4\)NO\(_{3(aq)}\) to generate ammonia gas. L is likely to be A. HCl B. NaOH C. CH3COOH D. CaSO4 Detailed SolutionThe reaction between NH\(_4\)NO\(_{3(aq)}\) and any metal hydroxide produces ammonia, water and an alkali metal nitrate. |
|
| 29. |
On heating, the following trioxocarbonate (IV) salts decompose to give solid residue except A. ammonium trioxocarbonate (IV) B. calcium trioxocarbonate (IV) C. lead (ll) trioxocarbonate(IV) D. zinc trioxocarbonate (IV) Detailed SolutionAmmonium trioxocarbonate (IV) is an unstable compound. It decomposes on heating to yield ammonia, carbon (IV) oxide and water. All of these are gases. |
|
| 30. |
Which of the following pH values indicates that a solution is a strong base? A. 1 B. 5 C. 9 D. 13 |
D |