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 601: An increase in the pressure exerted on gas at a constant temperature results in Options:
  A) a decrease in the number of effective collisions
  B) a decrease in volume
  C) an increase in the average intermolecular distance
  D) an increase in volume
  Show Answer
  The correct answer is B .
• Question 602:

  What is the common name for ethanoic acid?

  Options:
  A) Acetic acid
  B) Butyric acid
  C) Propionic acid
  D) Formic acid
  Show Answer
  The correct answer is A .
• Question 603:

  A sample of a gas exerts a pressure of 8.2 atm when confined in a 2.93 dm³ container at 20°C. The number of moles of gas in the sample is?

  (R = 0.082 litre atm / deg mole)

  Options:
  A) 1.00
  B) 2.00
  C) 3.00
  D) 4.00
  Show Answer
  The correct answer is A .
• Question 604: In the extraction of iron, the waste gas from the furnace is a mixture of Options:
  A) PH₃ CO and CO₂
  B) CO and C
  C) N₂ CO and CO₂
  D) PH₃ and CO
  Show Answer
  The correct answer is A .
• Question 605:

  Which of the following methods is commonly used to remove suspended impurities from water?

  Options:
  A) Fluoridation
  B) Chlorination
  C) Filtration
  D) Distillation
  Show Answer
  The correct answer is C .
• Question 606: An undesirable paraffin in the petroleum industry which is particularly prone to knocking is? Options:
  A) iso-octane
  B) n-heptane
  C) iso-heptane
  D) n-octane
  Show Answer
  The correct answer is B .
• Question 607: The following arrangement of elements in order of decreasing number of outer electrons; One of the elements is wrongly placed. Which is it? ALUMINIUM, CHLORINE, SILICON, MAGNESIUM AND SODIUM. Options:
  A) chlorine
  B) aluminium
  C) silicon
  D) magnesium
  E) sodium
  Show Answer
  The correct answer is B .
• Question 608: The metal that liberates hydrogen from cold water in bubbles only is Options:
  A) Na
  B) K
  C) Ca
  D) Al
  Show Answer
  The correct answer is C .
• Question 609:

  The scientist who stated that matter can be converted into energy is?

  Options:
  A) Boyle
  B) Lavoiser
  C) Avogadro
  D) Einstein
  Show Answer
  The correct answer is D .
• Question 610: When sodium dioxonitrate (lll) (NaNO₂) dissolves in water, ∆H is positive. The process of dissolution is Options:
  A) exothermic
  B) endothermic
  C) isothermal
  D) isomeric
  E) hygroscopic
  Show Answer
  The correct answer is B .