Year :
1990
Title :
Chemistry
Exam :
WASSCE/WAEC MAY/JUNE
Paper 1 | Objectives
11 - 20 of 32 Questions
| # | Question | Ans |
|---|---|---|
| 11. |
How many molecules are there in 14g of nitrogen gas at s.t.p? (n = 14, Avogadro Number = 6. 0 x 1023 mol-1) A. 1.2 x 10 23 B. 3.0 x 1023 C. 6.0 x1023 D. 1.2 x 1024 E. 30 x1023 |
C |
| 12. |
Which of the following correctly explains entropy? A. the natural tendency for a system to achieve a greater disorder B. a balance of two driving forces between free energy and enthalpy changes C. the cause of spontaneity of a reaction D. a measure of the enthalpy of a reaction E. a measure of the rate of attaining equilibrum in a reversible reaction |
A |
| 13. |
The gas that is liberated when iron is heated with concentrated tetraoxosulphate (VI)acid is A. H2S B. \(SO_{2}\) C. HCI D. SO3 E. O2 Detailed Solution2Fe (s) + 6H2SO4 (l) → Fe2(SO4)3 (aq) + 3SO2 (g) + 6H2O (l) |
|
| 14. |
Which of the following salts in aqueous solution will have a pH greater than 7? A. NaCl B. ACI3 C. FeCI3 D. Na 2SO4 E. K 2CO3 |
E |
| 15. |
The compound of copper which is used in electroplating dyeing, printing, wood preservation and as a fungicide is A. copper (ll) hydroxide B. copper (ll) trioxonitrate (V) pentahydrate C. copper (ll) tetraoxosulphate (VI) pentahydrate D. copper (ll) oxide E. copper (ll) trioxocarbonate (lV) |
C |
| 16. |
What is the molecular formula of a compound whose empirical formula is CH2O and molar mass is 180? (H = 1, C = 12, O = 16) A. C 4H 8O2 B. C 4H 8O3 C. C 6H 10O5 D. C 6H 12O6 E. C 12H 22O11 |
D |
| 17. |
MO and X 2O represent the formula of oxides of elements M and X respectively . If M and X should combine to form a separate compound, what would be the formula of the compound? A. MX2 B. M2X C. MX D. M3X2 E. MX3 |
A |
| 18. |
Which of the following pollutants is biodegradable ? A. Sewage B. Plastics C. Metal scrape D. Lead compounds E. Hydrogen sulphide |
A |
| 19. |
In the reaction represented by the equation; 2FeCI3 + SO2 + 2H2O → 2FeCL2 + H2SO4 + 2HCI the oxidation number of sulphur changes from A. +2 to + 6 B. + 4 to + 6 C. 0 to + 6 D. - 2 to + 4 E. +2 to + 4 |
B |
| 20. |
Which of the following equations represents the reaction leading to the removal of permanent hardness of water? A. Ca(HCO 3)2 → CaCO3 + H2O + CO2 B. MgSO4 + Na 2CO3 + Na 2SO C. Ca(OH) 2 + 2HCI → CaCI 2 + 2H 2O D. Ca(HCO3)2 + Ca(OH)3 → 2CaCO3 + 2H2O E. MgSO4 + BaCI2 → MgCI2 + BaSO4 |
B |
| 11. |
How many molecules are there in 14g of nitrogen gas at s.t.p? (n = 14, Avogadro Number = 6. 0 x 1023 mol-1) A. 1.2 x 10 23 B. 3.0 x 1023 C. 6.0 x1023 D. 1.2 x 1024 E. 30 x1023 |
C |
| 12. |
Which of the following correctly explains entropy? A. the natural tendency for a system to achieve a greater disorder B. a balance of two driving forces between free energy and enthalpy changes C. the cause of spontaneity of a reaction D. a measure of the enthalpy of a reaction E. a measure of the rate of attaining equilibrum in a reversible reaction |
A |
| 13. |
The gas that is liberated when iron is heated with concentrated tetraoxosulphate (VI)acid is A. H2S B. \(SO_{2}\) C. HCI D. SO3 E. O2 Detailed Solution2Fe (s) + 6H2SO4 (l) → Fe2(SO4)3 (aq) + 3SO2 (g) + 6H2O (l) |
|
| 14. |
Which of the following salts in aqueous solution will have a pH greater than 7? A. NaCl B. ACI3 C. FeCI3 D. Na 2SO4 E. K 2CO3 |
E |
| 15. |
The compound of copper which is used in electroplating dyeing, printing, wood preservation and as a fungicide is A. copper (ll) hydroxide B. copper (ll) trioxonitrate (V) pentahydrate C. copper (ll) tetraoxosulphate (VI) pentahydrate D. copper (ll) oxide E. copper (ll) trioxocarbonate (lV) |
C |
| 16. |
What is the molecular formula of a compound whose empirical formula is CH2O and molar mass is 180? (H = 1, C = 12, O = 16) A. C 4H 8O2 B. C 4H 8O3 C. C 6H 10O5 D. C 6H 12O6 E. C 12H 22O11 |
D |
| 17. |
MO and X 2O represent the formula of oxides of elements M and X respectively . If M and X should combine to form a separate compound, what would be the formula of the compound? A. MX2 B. M2X C. MX D. M3X2 E. MX3 |
A |
| 18. |
Which of the following pollutants is biodegradable ? A. Sewage B. Plastics C. Metal scrape D. Lead compounds E. Hydrogen sulphide |
A |
| 19. |
In the reaction represented by the equation; 2FeCI3 + SO2 + 2H2O → 2FeCL2 + H2SO4 + 2HCI the oxidation number of sulphur changes from A. +2 to + 6 B. + 4 to + 6 C. 0 to + 6 D. - 2 to + 4 E. +2 to + 4 |
B |
| 20. |
Which of the following equations represents the reaction leading to the removal of permanent hardness of water? A. Ca(HCO 3)2 → CaCO3 + H2O + CO2 B. MgSO4 + Na 2CO3 + Na 2SO C. Ca(OH) 2 + 2HCI → CaCI 2 + 2H 2O D. Ca(HCO3)2 + Ca(OH)3 → 2CaCO3 + 2H2O E. MgSO4 + BaCI2 → MgCI2 + BaSO4 |
B |