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 1591: (1 /(2) N_2(g) + (1) / (2)O_2(g) → NO_(g) ∆H° 89 KJ mol^-. If the entropy change for the reaction above at 25°C is 11.8 J mol^-, calculate the change in free energy. ∆G°, for the reaction at 25°C? Options:
  A) 88.71 KJ
  B) 85.48 KJ
  C) -204.00 KJ
  D) -3427.40 KJ
  Show Answer
  The correct answer is D .
• Question 1592: If the electron configuration of a element is p1s² 2s² 2P⁵, how many unpaired electron are there? Options:
  A) 2
  B) 8
  C) 1
  D) 4
  Show Answer
  The correct answer is C .
• Question 1593:

  

  The compound above exhibits

  Options:
  A) geometric isomerism
  B) optical isomerism
  C) structural isomerism
  D) positional isomerism
  Show Answer
  The correct answer is B .
• Question 1594: A sample of temporary hard water can be prepared in the laboratory by? Options:
  A) disolving calcium chloride in distilled water
  B) saturating lime water with carbon (IV) oxide
  C) saturating distilled water with calcium hydroxide
  D) dissolving sodium hydrogen trioxocarbonate (IV) in some distilled water
  Show Answer
  The correct answer is B .
• Question 1595: The confirmatory test for alkanoic acids in organic qualitative analysis is the? Options:
  A) turning of wet blue litmus paper red
  B) reaction with alkanols to form esters
  C) reaction with sodium hydroxide to form salt and water
  D) reaction with aqueous Na₂COsp₃ to liberate a gas which turns lime water milky
  Show Answer
  The correct answer is B .
• Question 1596: How many cations will be produced from a solution of potassium aluminium tetraoxosulphate (VI)? Options:
  A) 3
  B) 4
  C) 1
  D) 2
  Show Answer
  The correct answer is D .
• Question 1597: Which of the following compounds is NOT the correct product formed when the parent metals is heated in air? Options:
  A) Calcium oxide (CaO)
  B) Sodium oxide (Na₂O)
  C) Copper (ll) oxide (CuO)
  D) Tri-iron tetroxide (Fe₃O₄)
  E) Aluminium oxide (Al₂O₃)
  Show Answer
  The correct answer is D .
• Question 1598: The hydroxyl ion concentrated, (OH^-), in a solution of sodium hydroxide of pH 10.0 is? Options:
  A) 10^-10 mol dm^-3
  B) 10^-6 mol dm^-3
  C) 10^-4 mol dm^-3
  D) 10^-2 mol dm^-3
  Show Answer
  The correct answer is C .
• Question 1599: Local black soap is made by boiling palm oil with liquid extract of ash. The function of the ash is to provide the? Options:
  A) acid
  B) ester of allanoic acid
  C) alkali
  D) alkanol
  Show Answer
  The correct answer is C .
• Question 1600:

  

  The I.U.P.A.C name for the compound is

  Options:
  A) isopropylethene
  B) acetylene
  C) 3- methylbutane
  D) 2-methylbutane
  E) 5-methylpentane
  Show Answer
  The correct answer is D .