Year :
2020
Title :
Chemistry
Exam :
WASSCE/WAEC MAY/JUNE
Paper 1 | Objectives
21 - 30 of 49 Questions
| # | Question | Ans |
|---|---|---|
| 21. |
Which of the following compounds has the lowest boiling point? A. C\(_4\)H\(_10\) B. CH\(_3\)COOH C. H\(_2\)O D. C\(_2\)H\(_5\)OH Detailed Solution117.7 °C118 °C 100 °C 78.37 °C |
|
| 22. |
An alkanol containing 60% carbon by mass would have a molecular formula [H=1.0. C-12.0, O= 16.0] A. CH\(_3\)OH B. C\(_2\)H\(_5\)OH C. C\(_3\)H\(_7\)OH D. C\(_4\)H\(_9\)OH |
C |
| 23. |
Which of the following compounds would release hydrogen when reacted with sodium metal? I. CH\(_3\)COOHII. CH\(_3\)CH\(_2\)OHIII. CH\(_3\)COOCH\(_3\) A. I only B. I and II only C. Il and IIl only D. I and Ill only |
B |
| 24. |
Which of the following substances is not a reducing agent? A. C B. CO C. O\(_2\) D. H\(_2\) Detailed Solution- A reducing agent is oxidized, because it loses electrons in the redox reaction.- Elemental oxygen is a strong oxidizing agent. |
|
| 25. |
Which of the following statements is correet for a reaction at equilibrium? A. All reactions cease to occur B. The eaction has gone to completion C. The rates of the forward and backward reactions are equal D. The amount of product equals the amount of reactants Detailed SolutionIn a chemical reaction, chemical equilibrium is the state in which the forward reaction rate and the reverse reaction rate are equal. The result of this equilibrium is that the concentrations of the reactants and the products do not change. |
|
| 26. |
Which of the following reactions are always exothermic? 1. Neutralization Il. Decomposition III. Combustion A. I and II only B. I and III only C. II and IIl only D. I, II and III Detailed Solution
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| 27. |
Which of the following standard conditions is not correct about energy changes? A. Standard temperature is 298K B. Standard pressure is 1 atm C. Concentration of solution must be 1 mol/dm\(^3\) D. ΔH at 298 K is the activation energy Detailed Solutionthe standard conditions of 1 atm pressure and 298K. |
|
| 28. |
F 5.0 cm\(^-3\) of 0.200 mol dm(^-3\) Na\(_2\)CO\(_3\) was diluted to 250cm(^-3\) solution, what would be the concentration of the resulting solution? A. 0.004 mol dm(^-3\) B. 0.020 mol dm(^-3\) C. 0.200 mol dm(^-3\) D. 0.400 mol dm(^-3\) Detailed Solution
 0.200 X 5.00 = M\(_2\) X 250 M\(_2\) = 1 / 250 M\(_2\) = 0.004 mol dm(^-3\) |
|
| 29. |
The initial volume and pressure of a given mass of gas is V and 3.P. What is its pressure if its volume is increased to 2V at constant temperature? A. 3 P B. 2P C. \(frac{3}{2}\) P D. \(frac{2}{3}\) P |
C |
| 30. |
What volume of oxygen at s.t.p is required to burn completely 7.5 dm\(^3\) of methane according to the following equation?CH\(_4\) \(_g\) + 20\(_2\) \(_g\) → CO\(_2\) \(_g\) + H\(_2\)O\(_g\) A. 3.75 dm\(^3\) B. 7.59 dm\(^3\) C. 15.0 dm\(^3\) D. 30.0dm\(^3\) Detailed Solution1 mole of methane reacts with 2 moles of oxygen1 vol of methane reacts with 2 vol of oxygen : 7.5 vol of methane will yield 15 vol of oxygen in dm\(^3\) |
| 21. |
Which of the following compounds has the lowest boiling point? A. C\(_4\)H\(_10\) B. CH\(_3\)COOH C. H\(_2\)O D. C\(_2\)H\(_5\)OH Detailed Solution117.7 °C118 °C 100 °C 78.37 °C |
|
| 22. |
An alkanol containing 60% carbon by mass would have a molecular formula [H=1.0. C-12.0, O= 16.0] A. CH\(_3\)OH B. C\(_2\)H\(_5\)OH C. C\(_3\)H\(_7\)OH D. C\(_4\)H\(_9\)OH |
C |
| 23. |
Which of the following compounds would release hydrogen when reacted with sodium metal? I. CH\(_3\)COOHII. CH\(_3\)CH\(_2\)OHIII. CH\(_3\)COOCH\(_3\) A. I only B. I and II only C. Il and IIl only D. I and Ill only |
B |
| 24. |
Which of the following substances is not a reducing agent? A. C B. CO C. O\(_2\) D. H\(_2\) Detailed Solution- A reducing agent is oxidized, because it loses electrons in the redox reaction.- Elemental oxygen is a strong oxidizing agent. |
|
| 25. |
Which of the following statements is correet for a reaction at equilibrium? A. All reactions cease to occur B. The eaction has gone to completion C. The rates of the forward and backward reactions are equal D. The amount of product equals the amount of reactants Detailed SolutionIn a chemical reaction, chemical equilibrium is the state in which the forward reaction rate and the reverse reaction rate are equal. The result of this equilibrium is that the concentrations of the reactants and the products do not change. |
| 26. |
Which of the following reactions are always exothermic? 1. Neutralization Il. Decomposition III. Combustion A. I and II only B. I and III only C. II and IIl only D. I, II and III Detailed Solution
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| 27. |
Which of the following standard conditions is not correct about energy changes? A. Standard temperature is 298K B. Standard pressure is 1 atm C. Concentration of solution must be 1 mol/dm\(^3\) D. ΔH at 298 K is the activation energy Detailed Solutionthe standard conditions of 1 atm pressure and 298K. |
|
| 28. |
F 5.0 cm\(^-3\) of 0.200 mol dm(^-3\) Na\(_2\)CO\(_3\) was diluted to 250cm(^-3\) solution, what would be the concentration of the resulting solution? A. 0.004 mol dm(^-3\) B. 0.020 mol dm(^-3\) C. 0.200 mol dm(^-3\) D. 0.400 mol dm(^-3\) Detailed Solution
0.200 X 5.00 = M\(_2\) X 250 M\(_2\) = 1 / 250 M\(_2\) = 0.004 mol dm(^-3\) |
|
| 29. |
The initial volume and pressure of a given mass of gas is V and 3.P. What is its pressure if its volume is increased to 2V at constant temperature? A. 3 P B. 2P C. \(frac{3}{2}\) P D. \(frac{2}{3}\) P |
C |
| 30. |
What volume of oxygen at s.t.p is required to burn completely 7.5 dm\(^3\) of methane according to the following equation?CH\(_4\) \(_g\) + 20\(_2\) \(_g\) → CO\(_2\) \(_g\) + H\(_2\)O\(_g\) A. 3.75 dm\(^3\) B. 7.59 dm\(^3\) C. 15.0 dm\(^3\) D. 30.0dm\(^3\) Detailed Solution1 mole of methane reacts with 2 moles of oxygen1 vol of methane reacts with 2 vol of oxygen : 7.5 vol of methane will yield 15 vol of oxygen in dm\(^3\) |