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 1241:

  The volume of 2.5 moles of oxygen at s.t.p is

  [Molar volume of a gas at s.t.p = 22.4 dm³]

  Options:
  A) 50.0 dm³
  B) 84.0 dm³
  C) 28.0 dm³
  D) 56.0 dm³
  Show Answer
  The correct answer is D .
• Question 1242: The number of atoms of chlorine present in 5.85g of NaCl is [Avogaro's Number = 6.02 x 10²³] Options:
  A) 6.02 x 10²²
  B) 5.85 x 10²³
  C) 6.02 x 10²³
  D) 5.85 x 10²⁴
  Show Answer
  The correct answer is A .
• Question 1243: Which of these salts will produce its metal, oxygen and nitrogen (IV) oxide on heating? Options:
  A) Silver and trioxonitrate (V)
  B) Sodium trioxonitrate (V)
  C) Calcium trioxonitrate (V)
  D) Lithium trioxonitrate (V)
  Show Answer
  The correct answer is A .
• Question 1244: The products of the thermal decomposition of ammonium trioxonitrate (V) are Options:
  A) NO ₂ and oxygen
  B) NH₃ and oxygen
  C) nitrogen and water
  D) N₂O and water
  Show Answer
  The correct answer is D .
• Question 1245: Which volume of 0.5 M H ₂SO₄ will exactly neutralize 20 cm ³ of 0.1 M NaOH solution? Options:
  A) 2.0 cm ³
  B) 5.0 cm ³
  C) 6.8 cm ³
  D) 8.3 cm ³
  E) 10.4 cm ³
  Show Answer
  The correct answer is A .
• Question 1246: Water is said to be temporarily hard when it contains Options:
  A) Ca (HCO₃)₂ and Mg (HCO₃)₂ salts
  B) Ca (HCO₃)₂ and CaCO₃ SALTS
  C) Mg(HCO₃)₂ and CaSO₄ salts
  D) CaSO₄ and Ca(HCO₃)₂ salts
  Show Answer
  The correct answer is A .
• Question 1247: The shape of the carbon (lV) oxide molecule is Options:
  A) pyramidal
  B) linear
  C) angular
  D) tetrahedral
  Show Answer
  The correct answer is B .
• Question 1248:

  2H₂S_(g) + SO_2(g) + H₂O_(l) → 3S_(s) + 3H₂O_(l)..........(I)

  3CuO_(s) + 2NH_3(g) → 3Cu_(s) + 3H₂O_(l) + N_2(g).........(II)

  In the equations above, the oxidizing agent (I) and the reducing agent in (II) respectively are?

  Options:
  A) H₂S and NH₃
  B) SO₂ and CuO
  C) SO₂ and NH₃
  D) H₂S and CuO
  Show Answer
  The correct answer is C .
• Question 1249: In the preparation of ammonia, which of the following is used as the drying agent? Options:
  A) CaO
  B) CaCI₂
  C) Conc. H₂SO₄
  D) P₂O₅
  E) H₃PO₄
  Show Answer
  The correct answer is A .
• Question 1250:

  What mass of K₂CrO₄ is required to prepare 250cm³ of 0.020 mol dm³ solution?

  [K₂CrO₄ = 194.2g mol^-1]

  Options:
  A) 0.97g
  B) 9.70g
  C) 19.42g
  D) 97.10g
  Show Answer
  The correct answer is A .