Year :
2001
Title :
Chemistry
Exam :
WASSCE/WAEC MAY/JUNE
Paper 1 | Objectives
41 - 50 of 52 Questions
| # | Question | Ans |
|---|---|---|
| 41. |
The gas given off when NH4Cl is heated with an alkali is A. H2 B. CI2 C. N 2 D. NH 3 |
D |
| 42. |
A major factor coonsidered in selecting a suitable method for preparing a simple salt is its A. crystalline form B. melting point C. reactivity with dilute acids D. solubility in water |
D |
| 43. |
Which of the following acids forms normal salts only? A. Tetraoxosulphate (VI) acid B. Trioxosulphate (IV) acid C. Tetraoxophosphate (V) acid D. Trioxonitrate (V) acid |
D |
| 44. |
A substance is said to be hygroscopic if it absorbs? A. water from the atmosphere to form a solution B. heat from the surrounding C. carbon (IV) oxide from the atmosphere D. moisture from the atmosphere without dissolving Detailed SolutionHygroscopy is the phenomenon of attracting and holding water molecules via either absorption or adsorption from the surrounding environment,which is usually at normal or room temperature. Deliquescence, the process by which a substance absorbs moisture from the atmosphere until it dissolves in the absorbed water and forms a solution. |
|
| 45. |
Which of the following substances increases in mass when heated in air? A. Sodium chloride B. lodine crystals C. magnesium ribbon D. copper (ll) oxide |
C |
| 46. |
Calculate the mass of sodium hydroxide in 5.00 dm3 of a 0.125 mol dm-3 solution [NaOH = 40 g mol A. 0.0156 g B. 0.625 g C. 1.00 g D. 0 g Detailed Solution1 mole of NaOH per dm3 has a mass of 40g mass of NaOH in 0.125 mole = 0.125 x 40 = 5g mass in 5.00 dm3 of the solution = 5 x 5 = 25.0g |
|
| 47. |
Which of the following salt solutions will have a pH greater than 7? A. NaCl(aq) B. Na2CO3(aq) C. Na2SO4(aq) D. NaHSO4(aq) |
B |
| 48. |
What will happen if more heat is applied to the following system at equilibrium? X2(g) + 3Y 2(g) ⇌ 2XY3(g); ∆H =-kJmol -1 A. the yield of XY 3 will decompose B. more of XY3 will decompose C. More of X2 will react D. the forward reaction will go to completion |
B |
| 49. |
Equal amounts of marble chips are reacted separately with 100cm3 of hydrochloric acid of different concentrations . if all the marble chips reacted, which of the following remained the same in each case? A. Average rate of evolution of gas B. Total mass of gas evolved during the reaction C. Time taken for the reaction to reach completion D. lnitial reaction rates |
B |
| 50. |
CuSO4 5H2O can be obtained from an aqueous solution of copper (ll) tetraoxosulphate (VI) by A. evaporation to dryness B. using chromatography C. precipitation D. crystallization |
D |
| 41. |
The gas given off when NH4Cl is heated with an alkali is A. H2 B. CI2 C. N 2 D. NH 3 |
D |
| 42. |
A major factor coonsidered in selecting a suitable method for preparing a simple salt is its A. crystalline form B. melting point C. reactivity with dilute acids D. solubility in water |
D |
| 43. |
Which of the following acids forms normal salts only? A. Tetraoxosulphate (VI) acid B. Trioxosulphate (IV) acid C. Tetraoxophosphate (V) acid D. Trioxonitrate (V) acid |
D |
| 44. |
A substance is said to be hygroscopic if it absorbs? A. water from the atmosphere to form a solution B. heat from the surrounding C. carbon (IV) oxide from the atmosphere D. moisture from the atmosphere without dissolving Detailed SolutionHygroscopy is the phenomenon of attracting and holding water molecules via either absorption or adsorption from the surrounding environment,which is usually at normal or room temperature. Deliquescence, the process by which a substance absorbs moisture from the atmosphere until it dissolves in the absorbed water and forms a solution. |
|
| 45. |
Which of the following substances increases in mass when heated in air? A. Sodium chloride B. lodine crystals C. magnesium ribbon D. copper (ll) oxide |
C |
| 46. |
Calculate the mass of sodium hydroxide in 5.00 dm3 of a 0.125 mol dm-3 solution [NaOH = 40 g mol A. 0.0156 g B. 0.625 g C. 1.00 g D. 0 g Detailed Solution1 mole of NaOH per dm3 has a mass of 40g mass of NaOH in 0.125 mole = 0.125 x 40 = 5g mass in 5.00 dm3 of the solution = 5 x 5 = 25.0g |
|
| 47. |
Which of the following salt solutions will have a pH greater than 7? A. NaCl(aq) B. Na2CO3(aq) C. Na2SO4(aq) D. NaHSO4(aq) |
B |
| 48. |
What will happen if more heat is applied to the following system at equilibrium? X2(g) + 3Y 2(g) ⇌ 2XY3(g); ∆H =-kJmol -1 A. the yield of XY 3 will decompose B. more of XY3 will decompose C. More of X2 will react D. the forward reaction will go to completion |
B |
| 49. |
Equal amounts of marble chips are reacted separately with 100cm3 of hydrochloric acid of different concentrations . if all the marble chips reacted, which of the following remained the same in each case? A. Average rate of evolution of gas B. Total mass of gas evolved during the reaction C. Time taken for the reaction to reach completion D. lnitial reaction rates |
B |
| 50. |
CuSO4 5H2O can be obtained from an aqueous solution of copper (ll) tetraoxosulphate (VI) by A. evaporation to dryness B. using chromatography C. precipitation D. crystallization |
D |