Chemistry Exam Past Questions and Answers | JAMB, WAEC and NECO

Chemistry is the study of the substances that make up matter. It looks at their properties, how they react with each other, and how these reactions can create new substances.

• Question 1181:

  How many moles of limestone will be required to produce 5.6g of CaO?

  [Ca = 40, C = 12, O= 16]

  Options:
  A) 0.20 mol
  B) 0.10 mol
  C) 1.12 mol
  D) 0.56 mol
  Show Answer
  The correct answer is B .
• Question 1182: A solution of calcium bromide contains 20 g dm ³ What is the molarity of the solution with respect to calcium bromide and bromide ions? [Ca = 40, Br = 80] Options:
  A) 0. 1, 0 . 1
  B) 0. 1, 0. 2
  C) 0. 1, 0. 05
  D) 0.05, 0.1
  Show Answer
  The correct answer is C .
• Question 1183:

  

  In the diagram above, curve X represents the energy profile for a homogeneous gaseous reaction. Which of the following conditions would produce curve Y for the same reaction?

  Options:
  A) Increase in temperature
  B) Increase in the concentration of a reactant
  C) Addition of a catalyst
  D) Increase in pressure
  Show Answer
  The correct answer is C .
• Question 1184: A particle that contains 11 protons, 12 neutrons and 10 electrons is probably a Options:
  A) neutral non-metal
  B) metallic ion
  C) non-metallic ion
  D) neutral metal
  Show Answer
  The correct answer is B .
• Question 1185: zn + 2HCl → ZnCl₂ + H₂The rate of the above reaction will be greatly increased if Options:
  A) the zinc is in the powered form
  B) a greater volume of the acid is used
  C) a smaller volume of the acid is used
  D) the reaction vessel is immersed in an ice-bath
  E) the zinc is in the form of pellets
  Show Answer
  The correct answer is A .
• Question 1186: The property used in obtaining oxygen and nitrogen industrially from air is the? Options:
  A) boiling point
  B) density
  C) rate of diffusion
  D) solubility
  Show Answer
  The correct answer is A .
• Question 1187: Which of the following substances is a basic salt? Options:
  A) Na₂CO₃
  B) Mg(OH)CI
  C) NaHCO₃
  D) KSO₄.AI₂(SO₄)₃,24H₂O
  Show Answer
  The correct answer is B .
• Question 1188: X + Y = Z is an equilibrium reaction. The addition of a catalyst? Options:
  A) increase the amount of Z produced in a given time
  B) increases the rate of change in concentrations of X, Y and Z
  C) increases the rate of disapearance of X and Y
  D) increases the rate of the forward reaction
  E) decreases the amounts of X and Y left after the attainment of equilibrium
  Show Answer
  The correct answer is B .
• Question 1189: A metal that forms soluble trioxosulphate (IV) ion is Options:
  A) barium
  B) potassium
  C) manganese
  D) aluminium
  Show Answer
  The correct answer is B .
• Question 1190:

  

  In the diagram above the gas Y could be

  Options:
  A) hydrogen chloride
  B) oxygen
  C) carbon (IV) oxide
  D) chlorine
  Show Answer
  The correct answer is A .