Chemistry, 2015, WASSCE/WAEC MAY/JUNE, Exam, Paper 1 | Objectives

Paper Info

Year :

2015

Title :

Chemistry

Exam :

WASSCE/WAEC MAY/JUNE

Paper 1 | Objectives

21 - 30 of 50 Questions

#	Question	Ans
21.	The number of oxygen molecules present in 16.0g of the gas is ______? [Avogadro's number = 6.02 x 10²³] A. 6.02 x 10²² B. 6.02 x 10²³ C. 3.01 x 10²³ D. 1.51 x 10²³ Show Content Detailed Solution 1 mole = Molar mass of gas = Avogadros number 32g of O₂ = 6.02 x 10²³ 16g of O₂ = x x = \(\frac{16 \times 6.02 \times 10^23}{32}\) = 3.01 x 10²³	C
22.	Consider the following reaction equation: SO₄^2-_(aq) + 2H⁺_(aq) + ye^- \(\to\) SO₄^2-_(aq) + H₂O₍₁₎. The value of y in the equation is A. 2 B. 3 C. 4 D. 6 Show Content Detailed Solution from the reaction, the total charge on the left side = The total charge on the right side -2 + 2 + y = -2 : y = -2 : y = 2	A
23.	The general gas equation was deprived from______? A. Boyle's and Gay Lussac's laws B. Boyle's and Graham's laws C. Boyle's and Charles' laws D. Dalton's atomic theory	C
24.	The vapour pressure of a liquid depends on: I. Temperature II. rate of condensation III. Cohesive forces holding the particles together. A. I B. I and II C. I and III D. II and III	C
25.	Which of the following gases will diffuse most rapidly? [H = 1.00, C = 12.0, O = 16.0, S = 32.0, Cl = 35.5] A. Cl₂ B. SO₂ C. CH₄ D. C₂H₆	C
26.	When a reaction is endothermic, A. Enthalpy change, \(\Delta\)H is negative B. Heat content of a product is less than the heat content of a reactant C. Heat content of reactants is less than the heat content of product D. The reaction is non-spontaneous Show Content Detailed Solution An endothermic reaction is any chemical reaction that absorbs heat from its environment. The absorbed energy provides the activation energy for the reaction to occur.	C
27.	Which of the following statements about intermolecular distances and cohesive forces between gas is correct? They are A. Both large B. Both negligible C. Constant and negligible D. Large and negligible	B
28.	The following diagram illustrates the rate curve that was obtained when Mg reacted with excess dilute HCl. The diagram became horizontal at X because A. The reaction was slowed down B. All the dilute HCl has reacted C. All the Mg has reacted D. Hydrogen gas is produced at a steady rate	D
29.	An example of an acid salt is A. CH₃COOONa B. Mg(OH)Cl C. NaHSO₄ D. (NH₄)₂SO₄ Show Content Detailed Solution Acidic Salt: A normal salt which is formed by the neutralization of a strong acid and weak base is called acidic salt	C
30.	Which of the following oxides can be reduced by hydrogen? A. Aluminium oxide B. Magnesium oxide C. Sodium oxide D. Silver oxide	D

21.	The number of oxygen molecules present in 16.0g of the gas is ______? [Avogadro's number = 6.02 x 10²³] A. 6.02 x 10²² B. 6.02 x 10²³ C. 3.01 x 10²³ D. 1.51 x 10²³ Show Content Detailed Solution 1 mole = Molar mass of gas = Avogadros number 32g of O₂ = 6.02 x 10²³ 16g of O₂ = x x = \(\frac{16 \times 6.02 \times 10^23}{32}\) = 3.01 x 10²³	C
22.	Consider the following reaction equation: SO₄^2-_(aq) + 2H⁺_(aq) + ye^- \(\to\) SO₄^2-_(aq) + H₂O₍₁₎. The value of y in the equation is A. 2 B. 3 C. 4 D. 6 Show Content Detailed Solution from the reaction, the total charge on the left side = The total charge on the right side -2 + 2 + y = -2 : y = -2 : y = 2	A
23.	The general gas equation was deprived from______? A. Boyle's and Gay Lussac's laws B. Boyle's and Graham's laws C. Boyle's and Charles' laws D. Dalton's atomic theory	C
24.	The vapour pressure of a liquid depends on: I. Temperature II. rate of condensation III. Cohesive forces holding the particles together. A. I B. I and II C. I and III D. II and III	C
25.	Which of the following gases will diffuse most rapidly? [H = 1.00, C = 12.0, O = 16.0, S = 32.0, Cl = 35.5] A. Cl₂ B. SO₂ C. CH₄ D. C₂H₆	C

26.	When a reaction is endothermic, A. Enthalpy change, \(\Delta\)H is negative B. Heat content of a product is less than the heat content of a reactant C. Heat content of reactants is less than the heat content of product D. The reaction is non-spontaneous Show Content Detailed Solution An endothermic reaction is any chemical reaction that absorbs heat from its environment. The absorbed energy provides the activation energy for the reaction to occur.	C
27.	Which of the following statements about intermolecular distances and cohesive forces between gas is correct? They are A. Both large B. Both negligible C. Constant and negligible D. Large and negligible	B
28.	The following diagram illustrates the rate curve that was obtained when Mg reacted with excess dilute HCl. The diagram became horizontal at X because A. The reaction was slowed down B. All the dilute HCl has reacted C. All the Mg has reacted D. Hydrogen gas is produced at a steady rate	D
29.	An example of an acid salt is A. CH₃COOONa B. Mg(OH)Cl C. NaHSO₄ D. (NH₄)₂SO₄ Show Content Detailed Solution Acidic Salt: A normal salt which is formed by the neutralization of a strong acid and weak base is called acidic salt	C
30.	Which of the following oxides can be reduced by hydrogen? A. Aluminium oxide B. Magnesium oxide C. Sodium oxide D. Silver oxide	D