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 631: Nitrogen obtained from the liquefaction of air has a higher density than that obtained from nitrogen containing compounds because the former contains Options:
  A) water vapour
  B) oxygen
  C) carbon (IV) oxide
  D) rare gases
  Show Answer
  The correct answer is D .
• Question 632: Which of the following derivatives of nitrogen affords an aqueous solution having a pH of less that 7? Options:
  A) N₂O
  B) NO
  C) NO₂
  D) NaNO₃
  E) NH₃
  Show Answer
  The correct answer is C .
• Question 633: Carbohydrates are large molecules with the molecular formula C _x (H₂O)_y. In which of the following pairs is x not equal to y? Options:
  A) glucose and starch
  B) maltose and starch
  C) sucrose and fructose
  D) maltose and starch
  Show Answer
  The correct answer is A .
• Question 634:

  The heat of reaction can be determined experimentally using a device called a

  Options:
  A) Calorimeter
  B) Barometer
  C) Spectrometer
  D) Thermometer
  Show Answer
  The correct answer is A .
• Question 635: Which of the following can have an isomer? Options:
  A) C₂H₄
  B) C₄H₁₀
  C) C₃H₈
  D) C₂H₆
  E) C₆H₆
  Show Answer
  The correct answer is B .
• Question 636:

  Which of the following statements is true for strong electrolytes?

  Options:
  A) They do not conduct electricity in the molten state
  B) They completely dissociate into ions in solution
  C) They are non-polar substances
  D) They partially dissociate into ions in solution
  Show Answer
  The correct answer is B .
• Question 637: X_(g) + 3Y_(g) ---- 2z_(g) H = +ve. if the reaction above takes place at room temperature, the G will be Options:
  A) negative
  B) zero
  C) positive
  D) indeterminate
  Show Answer
  The correct answer is D .
• Question 638:

  

  Use the following option above to answer this question. Which of the following compounds in solution will turn red litmus paper blue?

  Options:
  A) A
  B) B
  C) C
  D) D
  Show Answer
  The correct answer is C .
• Question 639: The chemicals used to soften hard water involves the addition of Options:
  A) insoluble sodium compounds which from soluble solutions of calcium and magesium
  B) solube soudium compounds which from soluble solutions of calcium and magnesium ions
  C) solube sodium compounds which from insoluble precipitates of calcium and magnesium ions
  D) insoluble precipitates of calcium and magnesium ions
  Show Answer
  The correct answer is C .
• Question 640: The method that can be used to convert hard water to soft water is Options:
  A) chlorination
  B) passage over activated charcoal
  C) the use of an ion-exchange resin
  D) aeration
  Show Answer
  The correct answer is C .