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 511:

  Sodium reacts vigorously with water to produce

  Options:
  A) Sodium chloride (NaCl) and oxygen gas (O2)
  B) Sodium nitrate (NaNO3) and water (H2O)
  C) Sodium hydroxide (NaOH) and hydrogen gas (H2)
  D) Sodium oxide (Na2O) and hydrogen gas (H2)
  Show Answer
  The correct answer is C .
• Question 512: Palm wine turns sour with time because? Options:
  A) the sugar content is converted into alcohol
  B) the carbon (IV) oxide formed during the fermentation process has a sour taste
  C) it is commonly adulterated by the tappers and sellers
  D) microbial activity results in the production of orgain acids within it
  Show Answer
  The correct answer is D .
• Question 513: Which of the following processes NOT lead to a chemical change? Options:
  A) Strirring iron in sulphur (IV) acid
  B) Stirring sodium carbonate in water
  C) Stirring glucose in concentrated sulphur (IV) acid
  D) Mixing sulphur (IV) acid with potassium carbonate
  E) Titrating an acid against base
  Show Answer
  The correct answer is B .
• Question 514:

  What is the IUPAC name for the following compound? HC$\equiv$CCH${}_3$

  Options:
  A) Acetylene
  B) Methyl acetylene
  C) Butanol
  D) Decanoic acid
  Show Answer
  The correct answer is B .
• Question 515: The energy change (ΔH) for the reaction CO(g) + (1)/(2)O_2(g) → is?(ΔHi(CO) = -110.4 kJ mol^-) (ΔHi(CO₂) = -393 kJ mol^-) Options:
  A) -503.7 kJ
  B) +503.7kJ
  C) -282.9 kJ
  D) +282.9 kJ
  E) +393.3 kJ
  Show Answer
  The correct answer is C .
• Question 516: The isomers of C₃H₈O ARE Options:
  A) 1 - propanol and 2 - propanol
  B) 1 - propanol and 1 - propanol
  C) 2 - propanol and 2 - propanone
  D) 2 - propanol and 1 - propanol
  Show Answer
  The correct answer is A .
• Question 517: An isotope has an atomic number of 17 and a mass number of 36. Which of the following gives the correct number of neutrons and protons in an atom of the isotope? Options:
  A) Neutrons 53, Protons 17
  B) Neutrons 17, Protons 36
  C) Neutrons 19, Protons 17
  D) Neutrons 36, Protons 17
  Show Answer
  The correct answer is C .
• Question 518:

  Which of the following are chemical changes?

  I. cooking of food
  II. digestion of food
  III. freezing of water
  IV. water is heated up

  Options:
  A) I and II
  B) I, II, and III
  C) III and IV
  D) all of the above
  Show Answer
  The correct answer is A .
• Question 519:

  Which of the following statements is correct about the periodic table?

  Options:
  A) Elements in the same period have the same number of valence electrons
  B) The valence electrons of the elements in the same period increase progressively across the period
  C) Elements in the same group have the same number of electron shells
  D) The non-metallic Properties of the elements tend to decrease across each period
  Show Answer
  The correct answer is B .
• Question 520: Organic molecules that have the suffix-ene are unsaturated hydrocarbons that have Options:
  A) a single bond
  B) a double bond
  C) a triple bond
  D) an ionic bond
  Show Answer
  The correct answer is B .