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 581:

  An element having the atomic number 17 will resemble which of the following elements having atomic number as given below?

  Options:
  A) 33
  B) 35
  C) 18
  D) 19
  Show Answer
  The correct answer is B .
• Question 582:

  Which of the following are mixtures? 

  I. Petroleum 

  II. Rubber latex 

  III. Vulcanizer's solution 

  IV. Carbon sulphide

  Options:
  A) I, II and III
  B) I, II and IV
  C) I and II only
  D) I and IV
  Show Answer
  The correct answer is A .
• Question 583:

  Chromatography is used to separate components of mixture which differ in their rates of ?

  Options:
  A) diffusion
  B) migration
  C) reaction
  D) sedimentation
  Show Answer
  The correct answer is B .
• Question 584:

  

  The following graph demonstrates the rate of reaction between calcium carbonate (marble)and dilute hydrochloric acid. The graph shows that the rate of reaction is initially greatest when

  Options:
  A) the initial slope of the curve is steepest and this occur when small pieces of marble are used and is due to a small surface area of reactant
  B) the occur when large pieces of marble are used and is due to a small surface area of reactant
  C) the initial slope of the curve is steepest and this occurs when small pieces of marble are used and is due to a large surface area of reactant
  D) the initial slope of the curve is steepest and this occur when large surface area of reactant
  E) the initial slope of the curve is least steep and this occur when small pieces of marble are used and is due to the increased surface area of the reactant
  Show Answer
  The correct answer is C .
• Question 585: CaO_s + H₂O_(l) → Ca(OH)_2(s) ΔH -65 kj. The process represented by the above equation is known as? Options:
  A) dissolution
  B) slaking
  C) liming
  D) mortaring
  Show Answer
  The correct answer is B .
• Question 586:

  What happens when alkanoic acids react with alcohols in the presence of an acid catalyst?

  Options:
  A) Saponification
  B) Esterification
  C) Polymerization
  D) Hydrolysis
  Show Answer
  The correct answer is B .
• Question 587: An organic compound contains 60% carbon, 13.3% hydrogen and 26.7% oxygen. Calculate the empirical formula
  rn(C=12,H =1, O=16) Options:
  A) C ₅H ₁₂O
  B) C ₃H ₈O
  C) C ₆H ₁₃O ₂
  D) C ₄H ₉O
  Show Answer
  The correct answer is B .
• Question 588: What is the consequences of increasing pressure on the equilibrium reaction ZnO_(s) + H_2(g) Zn_(s) + H₂O_(I)? Options:
  A) The equilibrium is driven to the left
  B) The equilibrium is driven to the right
  C) There is no effect
  D) More ZnO is produced
  Show Answer
  The correct answer is C .
• Question 589:

  What happens to the position of equilibrium, if a reversible exothermic reaction is subjected to a decrease in temperature?

  Options:
  A) The position of equilibrium shifts to the left
  B) The position of equilibrium shifts to the right.
  C) The position of equilibrium remains unchanged
  D) The reaction stops
  Show Answer
  The correct answer is B .
• Question 590: Group VII elements are Options:
  A) monoatmic
  B) good oxidizing agents
  C) highly electropositive
  D) electron donors
  Show Answer
  The correct answer is B .