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 771:

  Which of the following is a form of calcium carbonate?

  I. limestone
  II. marble
  III. chalk
  Iv. egg-shells

  Options:
  A) I only
  B) I, II and IV
  C) I and II only
  D) I, II, III, and IV
  Show Answer
  The correct answer is D .
• Question 772: According to the kinetic theory an absence in temperature causes the kinetic energy of particles to Options:
  A) decrease
  B) increase
  C) remain constant
  D) be zero
  Show Answer
  The correct answer is D .
• Question 773:

  How many grams of H₂SO₄ are necessary for the preparation of 0.175 dm³ of M 6.00 M H₂SO₄?

  (S = 32.06, O = 16.00 H = 1.00)

  Options:
  A) 206.0 g
  B) 103.0 g
  C) 98.1 g
  D) 51.5 g
  Show Answer
  The correct answer is B .
• Question 774: Which of the following processes leads to increase in entropy? Options:
  A) Mixing a sample of NaCl and sand
  B) Condensation of water vapour
  C) Boiling a sample of water
  D) Cooling a saturated solution
  Show Answer
  The correct answer is C .
• Question 775: 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 776: Which of the following will have its mass increased when heated in air? Options:
  A) Helium
  B) Magnesium
  C) Copper pyrites
  D) Glass
  Show Answer
  The correct answer is B .
• Question 777: Carbohydrates are large molecules with the molecular formula C _x (H₂O)_y. In which of the following pairs is x not equal to y? Options:
  A) glucose and starch
  B) maltose and starch
  C) sucrose and fructose
  D) maltose and starch
  Show Answer
  The correct answer is A .
• Question 778:

  A solution X, on mixing with AgNO${}_3$ solution gives a white precipitate soluble in aqueous NH${}_3$, a solution Y, when also added to X, also gives a white precipitate which is soluble when heated solutions X and Y respectively contain

  Options:
  A) Al${}^{3+}$, Cl${}^{-}$
  B) Hg${}^{+}$, SO${}_4^{2-}$
  C) Pb${}^{2+}$, Cl${}^{-}$
  D) Ag${}^{+}$, SO${}_4^{2-}$
  Show Answer
  The correct answer is C .
• Question 779:

  How many alkoxyalkanes can be obtained from the molecular formula C${}_4$H${}_{10}$O?

  Options:
  A) 4
  B) 2
  C) 1
  D) 3
  Show Answer
  The correct answer is D .
• Question 780: Which of the following would support the conclusion that a solid sample is a mixture? Options:
  A) the solid can be ground to a fine powder
  B) the density of the solid is 2.25 g dm³
  C) the solid has a melting range of 300^oC to 375^oC
  D) the solid absorbs moisture from the atmosphere
  Show Answer
  The correct answer is C .