Year :
2000
Title :
Chemistry
Exam :
WASSCE/WAEC MAY/JUNE
Paper 1 | Objectives
11 - 20 of 45 Questions
| # | Question | Ans |
|---|---|---|
| 11. |
An element Z has a combining power of 3. Which of the following formulae is correct of its compounds? A. ZSO3 B. Z2CI3 C. Z2O3 D. ZS3 |
|
| 12. |
Which of the following increases as boiling water changes to steam? A. temperature of the system B. degree of disorder in the system C. number of molecules D. activation energy |
B |
| 13. |
9.60 g of a gas X occupies the same volume at 0.30 g of hydrogen under the same conditions. Calculate the molar mass of X [H = 1] A. 8g mol -1 B. 16 gmol -1 C. 32g mol -1 D. 64g mol -1 Detailed SolutionUsing the ideal gas equation,PV = nRT. where \(n = \frac{mass}{\text{molar mass}}\). For Hydrogen, \(\frac{m_H}{M_H} = \frac{PV}{RT}\). For element X, \(\frac{m_X}{M_X} = \frac{PV}{RT}\) Under the same conditions implies \(\frac{PV}{RT}\) is the same for both hydrogen and X. \(\frac{m_H}{M_H} = \frac{m_X}{M_X}\) Molar mass of X = \(\frac{\text{molar mass of hydrogen} \times \text{mass of X}}{\text{mass of hydrogen}}\) = \(\frac{1 \times 9.6}{0.3}\) = 32 g/mol |
|
| 14. |
Which of the following gases is colourless, odourless and soluble in potassium hydroxide solution? A. NO 2 B. SO 2 C. NH 2 D. CO3 |
D |
| 15. |
The gas evolved when dilute tetraoxosulphate (VI) acid reacts with sodium hydrogen trioxocarbonate (IV) is A. hydrogen B. oxygen C. carbon (IV) oxide D. sulphur (VI) oxide |
C |
| 16. |
If a solution has a pH of 2, it can be concluded that it A. is a weak electrolyte B. has hyrogen ion concentration of 0.2 mol sm-3 C. is twice as acidic as a solution of pH 1, D. will produce effervescence with magnesium ribbon |
D |
| 17. |
Which of the following salts is stable to heat? A. K2CO3 B. (NH4)2SO4 C. NaHCO 3 D. AgNO3 |
A |
| 18. |
Which of the following compounds dissolves in water to give an alkaline solution? A. Ammonium chloride B. Sodium chloride C. Sulphur (IV) oxide D. Potassium oxide |
D |
| 19. |
Which of the following salts is stable to heat? A. K 2CO 3 B. (NH 4) 2SO 4 C. NaHCO3 D. AgNO3 |
A |
| 20. |
What type of reaction is involved when wood shavings produce a brown gas with concentrated HNO3? A. Redox reaction B. Destructive distillation C. Dehydration D. Nutralization |
B |
| 11. |
An element Z has a combining power of 3. Which of the following formulae is correct of its compounds? A. ZSO3 B. Z2CI3 C. Z2O3 D. ZS3 |
|
| 12. |
Which of the following increases as boiling water changes to steam? A. temperature of the system B. degree of disorder in the system C. number of molecules D. activation energy |
B |
| 13. |
9.60 g of a gas X occupies the same volume at 0.30 g of hydrogen under the same conditions. Calculate the molar mass of X [H = 1] A. 8g mol -1 B. 16 gmol -1 C. 32g mol -1 D. 64g mol -1 Detailed SolutionUsing the ideal gas equation,PV = nRT. where \(n = \frac{mass}{\text{molar mass}}\). For Hydrogen, \(\frac{m_H}{M_H} = \frac{PV}{RT}\). For element X, \(\frac{m_X}{M_X} = \frac{PV}{RT}\) Under the same conditions implies \(\frac{PV}{RT}\) is the same for both hydrogen and X. \(\frac{m_H}{M_H} = \frac{m_X}{M_X}\) Molar mass of X = \(\frac{\text{molar mass of hydrogen} \times \text{mass of X}}{\text{mass of hydrogen}}\) = \(\frac{1 \times 9.6}{0.3}\) = 32 g/mol |
|
| 14. |
Which of the following gases is colourless, odourless and soluble in potassium hydroxide solution? A. NO 2 B. SO 2 C. NH 2 D. CO3 |
D |
| 15. |
The gas evolved when dilute tetraoxosulphate (VI) acid reacts with sodium hydrogen trioxocarbonate (IV) is A. hydrogen B. oxygen C. carbon (IV) oxide D. sulphur (VI) oxide |
C |
| 16. |
If a solution has a pH of 2, it can be concluded that it A. is a weak electrolyte B. has hyrogen ion concentration of 0.2 mol sm-3 C. is twice as acidic as a solution of pH 1, D. will produce effervescence with magnesium ribbon |
D |
| 17. |
Which of the following salts is stable to heat? A. K2CO3 B. (NH4)2SO4 C. NaHCO 3 D. AgNO3 |
A |
| 18. |
Which of the following compounds dissolves in water to give an alkaline solution? A. Ammonium chloride B. Sodium chloride C. Sulphur (IV) oxide D. Potassium oxide |
D |
| 19. |
Which of the following salts is stable to heat? A. K 2CO 3 B. (NH 4) 2SO 4 C. NaHCO3 D. AgNO3 |
A |
| 20. |
What type of reaction is involved when wood shavings produce a brown gas with concentrated HNO3? A. Redox reaction B. Destructive distillation C. Dehydration D. Nutralization |
B |