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 641: The mass number of an atom is? Options:
  A) the number of electrons in the atom
  B) the number of protons in the nucleus of the atom
  C) the number of neutrons in the nucleus of the atom
  D) the sum of numbers of electrons and protons inthe atom
  E) the sum of numbers of proton and neutrons in the nucleus of the atom
  Show Answer
  The correct answer is E .
• Question 642: When glowing splint is inserted into the mouth of a jar containing a gas, the splint is extinguished. The gas gives a white precipitate when passing into barium hydroxide. The gas is? Options:
  A) methane
  B) hydrogen chloride
  C) hydrogen
  D) nitrogen
  E) carbondioxide
  Show Answer
  The correct answer is E .
• Question 643:

  Burning magnesium ribbon in air removes which of the following

  (i) oxygen (ii) nitrogen (iii) argon and (iv) carbon(iv)oxide?

  Options:
  A) i and iv only
  B) i, ii, iii and iv only
  C) i only
  D) i and ii only
  Show Answer
  The correct answer is C .
• Question 644: The formula CH₂ for ethanoic acid is regarded as its Options:
  A) Molecular formula
  B) General formula
  C) Empirical formula
  D) Structural formula
  Show Answer
  The correct answer is C .
• Question 645:

  

  How many more isomers of the compound above can be obtained ?

  Options:
  A) 5
  B) 4
  C) 3
  D) 2
  Show Answer
  The correct answer is B .
• Question 646:

  What is Faraday's constant?

  Options:
  A) 6.022 x 10${}^{23}$ mol${}^{-1}$
  B) 3.00 x 10${}^8$ m/s
  C) 9.81 m/s${}^2$
  D) 96,485 C/mol
  Show Answer
  The correct answer is D .
• Question 647:

  

  The IUPAC nomenclature for the compound above is

  Options:
  A) 4-methylpent-1-ene
  B) 3-methylpent-2-ene
  C) 2-methylpent-1ene
  D) 2-methylpent-4-ene
  Show Answer
  The correct answer is A .
• Question 648:

  The two ions responsible for hardness in water are

  Options:
  A) Ca${}^{2+}$ and / or Mg${}^{2+}$
  B) K${}^{+}$ and / or Mg${}^{2+}$
  C) Ca${}^{2+}$ and / or Li${}^{+}$
  D) Ca${}^{2+}$ and / or Na${}^{+}$
  Show Answer
  The correct answer is A .
• Question 649: A trihydric alkanol is Options:
  A) Glycerol
  B) Phenol
  C) Glycol
  D) Ethanol
  Show Answer
  The correct answer is A .
• Question 650: Which of the following raw materials would be required from the smelting of iron ore in a blast furnace? Options:
  A) CaCO ₃
  B) Zn(NO₃)₂
  C) CuSO₄
  D) AICI₃
  E) CaSO₄
  Show Answer
  The correct answer is A .