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 1281: The element with the electron configuration 1s²2s²2p³ is Options:
  A) calcium
  B) chlorine
  C) oxygen
  D) nitrogen
  Show Answer
  The correct answer is D .
• Question 1282:

  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 1283:

  

  Use the graph above to answer this question.

  A sample, X, solid at room temperature, was melted, heated to a temperature of 358 K and allowed to cool as shown in OPQR. The section PQ indicates that X is

  Options:
  A) a mixture of salts
  B) a hydrated salt
  C) an ionic salt
  D) a pure compound
  Show Answer
  The correct answer is D .
• Question 1284:

  What is the percentage by mass of oxygen in Al₂(SO₄)₃. 2H₂O?

  [Al = 27, S = 32, H = 1, O = 16]

  Options:
  A) 14.29%
  B) 25.39%
  C) 50.79%
  D) 59.25%
  Show Answer
  The correct answer is D .
• Question 1285:

  An organic compound X has the following properties:
  I. It is not miscible with water.
  ll. It has boiling point of 77^oC.
  lll. It has a sweet odour.
  IV. lt is insoluble in sodium hydrogen carbonate solution.
  V lt does not decolourize bromine water.
  X is therefore

  Options:
  A) methane
  B) ethanoic acid
  C) ethene
  D) ethyl ethanoate
  E) carbon tetrachloride
  Show Answer
  The correct answer is D .
• Question 1286:

  Deliquescent substances are also?

  Options:
  A) efflorescent
  B) anhydrous
  C) hygroscopic
  D) insoluble
  Show Answer
  The correct answer is C .
• Question 1287:

  

  In the experiment above, X could be a solution of

  Options:
  A) sodium trioxonitrate (V) and ammonium chloride
  B) sodium trioxonitrate (lll) and ammonium chloride
  C) lead (ll) trioxonitrate (V) and copper turnings
  D) potassium trioxonitrate (V) and copper turnings
  Show Answer
  The correct answer is B .
• Question 1288:

  

  Use the figure above to answer this question. Which of the following is NOT a monomer?

  Options:
  A) A
  B) B
  C) C
  D) D
  Show Answer
  The correct answer is A .
• Question 1289:

  MnO_4(aq) + 8H⁺_(aq) + Y → Mn²⁺_(aq) + 4H₂O_(l)

  Y in the equation above represents

  Options:
  A) 2e^-
  B) 3e^-
  C) 5e^-
  D) 7e^-
  Show Answer
  The correct answer is C .
• Question 1290: The soft solder used for welding and plumbing is alloy of Options:
  A) lead and tin
  B) iron and tin
  C) lead and zinc
  D) iron and zinc
  Show Answer
  The correct answer is A .