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 451:

  What current in amperes will deposit 2.7g of aluminium in 2 hours?

  [Al = 27, F = 96 500 C mol^-1]

  Options:
  A) 32
  B) 8
  C) 4
  D) 16
  Show Answer
  The correct answer is C .
• Question 452:

  

  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 OP suggests that X is in the

  Options:
  A) liquid sate
  B) solid/liquid state
  C) solid state
  D) gaseous state
  Show Answer
  The correct answer is A .
• Question 453: A small quantity of solid ammonium chloride (NH4Cl) texted gently in a test tube, the solid gradually disappear produce two gases. Later, a white cloudy deposit was absence on the cooler part of the test tube. The ammonium chloride is to have undergo Options:
  A) distillation
  B) sublimation
  C) precipitation
  D) evaporation
  Show Answer
  The correct answer is B .
• Question 454: Which of the following statements is correct about the periodic table? Options:
  A) Elements in the same group have the same number of electron shells
  B) The non-metallic properties of the elements tend to decrease across each period
  C) Elements in the same period have the same number of valence electrons
  D) The valence electrons of the elements increase progressively across the period
  Show Answer
  The correct answer is D .
• Question 455: Sodium hydroxide (NaOH) pellets are Options:
  A) deliquescent
  B) hygroscopic
  C) efflorescent
  D) hydrated
  E) fluorescent
  Show Answer
  The correct answer is A .
• Question 456: Which of the following compounds is a base? Options:
  A) CO₂
  B) CaO
  C) H₃PO₃
  D) CH₃COOCH₃
  Show Answer
  The correct answer is B .
• Question 457:

  

  Choose the correct option from the structure above

  Options:
  A) A
  B) B
  C) C
  D) D
  Show Answer
  The correct answer is C .
• Question 458: Carbon (II) oxide is considered dangerous if inhaled mainly because it Options:
  A) can cause injury to the nervous system
  B) competes with oxygen in the blood
  C) competes with carbon (IV) oxide in the blood
  D) can cause lung cancer
  Show Answer
  The correct answer is B .
• Question 459:

  I. Treatment of cancerII. Detection of leakages in water mainsIII. Detection of the ages of ancient toolsIV. Preparation of drugs

  Which combination of the above refers to the uses of radioactive isotopes?

  Options:
  A) I and III
  B) I and II
  C) I, II and III
  D) I, II, III and IV
  Show Answer
  The correct answer is C .
• Question 460: Which of the following sulphides is insoluble in dilute HCl? Options:
  A) Na₂S
  B) ZnS
  C) CuS
  D) FeS
  Show Answer
  The correct answer is C .