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 61: Environmental pollution is worsened by the release from automobile exhausts of Options:
  A) Water vapour
  B) Steam
  C) Smoke
  D) Heavy metals
  Show Answer
  The correct answer is C .
• Question 62:

  P_(g) + Q_(g) ↔ 3R_(s) + S_(g) ΔH is negative

  Which of the following will increase the yield of R?

  Options:
  A) Using a larger close vessel
  B) Increasing the temperature
  C) Removing some S
  D) Adding a positive catalyst
  Show Answer
  The correct answer is C .
• Question 63: One of the products of the thermal decomposition of sodium trioxonitrate (V) is Options:
  A) sodium
  B) nitrogen
  C) sodium dioxonitrate (III)
  D) sodium oxide
  Show Answer
  The correct answer is C .
• Question 64: zn + 2HCl → ZnCl₂ + H₂The rate of the above reaction will be greatly increased if Options:
  A) the zinc is in the powered form
  B) a greater volume of the acid is used
  C) a smaller volume of the acid is used
  D) the reaction vessel is immersed in an ice-bath
  E) the zinc is in the form of pellets
  Show Answer
  The correct answer is A .
• Question 65:

  Which of the following compounds is an example of an electrovalent bond?

  Options:
  A) NaCl (sodium chloride)
  B) CO2 (carbon dioxide)
  C) H2O (water)
  D) CH4 (methane)
  Show Answer
  The correct answer is A .
• Question 66:

  The velocity, V of a gas is related to its mass, M by (k = proportionality constant)

  Options:
  A) V = $\frac{k}{M}$
  B) V = $\frac{k}{M^{\frac{1}{2}}}$
  C) V = $k{M}^2$
  D) V = $(\frac{k}{M}{)}^{\frac{1}{2}}$
  Show Answer
  The correct answer is B .
• Question 67: The simplest branched-chain hydrocarbon is Options:
  A) ethane
  B) ethene
  C) propane
  D) butane
  Show Answer
  The correct answer is D .
• Question 68:

  Which of the following substances is NOT hygroscopic?

  Options:
  A) Salt
  B) Sugar
  C) Silica gel
  D) Aluminum
  Show Answer
  The correct answer is D .
• Question 69:

  By what amount must the temperature of 200cm${}^3$ of Nitrogen at 27°C be increased to double the pressure if the final volume is 150cm${}^3$ (Assume ideality)

  Options:
  A) 150°C
  B) 177°C
  C) 75°C
  D) 120°C
  Show Answer
  The correct answer is B .
• Question 70:

  If the volume of a given mass of a gas at 0ºc is29.5cm${}^3$. What will be the volume of the gas at 15ºc, given that the pressure remains constant.

  Options:
  A) 31.6
  B) 62.2
  C) 32.7
  D) 31.1
  Show Answer
  The correct answer is D .