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 1461:

  2Cl_2(g) + 2H₂O_(g) 4HCl_(g) + O_2(g)

  ∆H° = +115KJ mol^-1. In the above equilibrium reaction, a decrease in temperature will?

  Options:
  A) favour the reverse reaction
  B) favour the forward reaction
  C) have no effect on the equilibrium state
  D) double the rate of the reverse raection
  Show Answer
  The correct answer is A .
• Question 1462: Which of the following pairs has compounds that are isomers? Options:
  A) Propanal and propanone
  B) Ethanoic acid and ethylmethanoate
  C) Ethanoic acid and ethane-1, 2-diol
  D) 2-methylbutane and 2, 2-dimethylbutane
  Show Answer
  The correct answer is D .
• Question 1463: The acid that is used to remove rust is Options:
  A) boric
  B) hydrochloric
  C) trioxonitrate (V)
  D) tetraoxosulphate (VI)
  Show Answer
  The correct answer is B .
• Question 1464: If 30cm³ of gas at 50^oC is warmed to 80^o at a fixed pressure, the fractional increase in volume is Options:
  A) 0.009
  B) 0.093
  C) 0.910
  D) 1.090
  Show Answer
  The correct answer is B .
• Question 1465: Magnesium (IV) oxide is known to hasten the decomposition of hydrogen peroxide. Its main action is to? Options:
  A) increase the surface area of the reactants
  B) increase the concntration of the reactants
  C) lower the activation energy for the reaction
  D) lower the heat of reaction, ∆H, for the reaction
  Show Answer
  The correct answer is C .
• Question 1466: The mass of an atom is determined by Options:
  A) its ionization potential
  B) its electrochemical potential
  C) the number of protons and electrons
  D) the number of neutrons and protons
  E) the number of neutrons and electrons
  Show Answer
  The correct answer is D .
• Question 1467: A mixture is different from a compound because Options:
  A) the properties of a compound are those of its individual constituents while those of a mixture differ from its constituents
  B) a mixture is always homogeneous while a compound is not
  C) the constituent of a compound are chemically bound together while those of a mixture are not
  D) a mixture can be represented by a chemical formula while a compound cannot
  Show Answer
  The correct answer is C .
• Question 1468: How many structural isomers can be drawn for the non-cyclic alkanol with molecular formula C ₄H₁₀O? Options:
  A) 1
  B) 2
  C) 3
  D) 4
  Show Answer
  The correct answer is D .
• Question 1469: The products of the combustion of candle wax are Options:
  A) hydrogen and water
  B) oxygen and water
  C) carbon (IV) oxide and water
  D) carbon (II) oxide and water
  Show Answer
  The correct answer is C .
• Question 1470:

  Electrons enter into orbitals in order of increasing energy as exemplified by?

  Options:
  A) 1S${}^2$2S${}^2$2PX${}^2$2py${}^2$2pz${}^0$3s${}^0$
  B) 1S${}^2$2S${}^2$2PX${}^2$2py${}^1$2pz${}^1$3s${}^0$
  C) 1S${}^2$2S${}^2$2PX${}^1$2py${}^1$2pz${}^1$3s${}^1$
  D) 1S${}^2$2S${}^2$2PX${}^2$2py${}^2$2pz${}^0$3s${}^1$
  Show Answer
  The correct answer is B .