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 1501:

  Calculate the volume in cm³ of oxygen evolved at s.t.p when a current of 5A is passed through acidified water for 193s?

  [F = 96500 C mol¹. Molar volume of a gas at s.t.p = 22.4dm³]

  Options:
  A) 0.056dm³
  B) 0.224dm³
  C) 224.000dm³
  D) 56.000dm³
  Show Answer
  The correct answer is A .
• Question 1502: The electronic configuration of Mg ²⁺ is Options:
  A) ls ²2s ²2P ⁶3s²3P²
  B) Is²2s²2P⁶
  C) ls²2s²2p⁶3s²
  D) ls²2s²2P⁴
  Show Answer
  The correct answer is B .
• Question 1503: The molar ratio of oxygen to nitrogen in dissolved air is 2:1 whereas the ratio is 4:1 in atmospheric air because? Options:
  A) nitrogen is less soluble than oxygen
  B) oxygen is heavier than nitrogen
  C) nitrogen has a higher partial pressure in air
  D) gases are hydrated in water
  Show Answer
  The correct answer is A .
• Question 1504: A side effect of soft water is that Options:
  A) it gives offensive taste
  B) excess calcium is precipitated
  C) it attcaks lead contained in pipes
  D) it encourages the growth of bacteria
  Show Answer
  The correct answer is C .
• Question 1505: 0.05 mol dm^-3 HCl is neutralized by 25 cm³ NaOH. If the volume of acid used is 32.00cm³, what is the concentration of the base Options:
  A) 0.016 mol dm^-3
  B) 0.032 mol dm^-3
  C) 0.039 mol dm^-3
  D) 0.064 mol dm^-3
  Show Answer
  The correct answer is D .
• Question 1506: The active reducing agent in the blast furnace for the extraction of iron is? Options:
  A) carbon
  B) limestone
  C) carbon(II)oxide
  D) calcium oxide
  Show Answer
  The correct answer is C .
• Question 1507: The energy changes accompanying the addition of an electron to a gaseous atom is called? Options:
  A) first ionization energy
  B) second ionization energy
  C) electron affinity
  D) electronegativity
  Show Answer
  The correct answer is C .
• Question 1508: What is discharged at the cathode during the electrolysis of copper (ll) tetraoxosulphate (VI) solution? Options:
  A) Cu ²⁺ only
  B) H + only
  C) Cu ²⁺ and H
  D) Cu ²⁺ and SO ^2-
  Show Answer
  The correct answer is A .
• Question 1509:

  In which of the following will hydrogen form ionic compound?

  Options:
  A) HCL
  B) NaH
  C) NH${}_3$
  D) CH${}_4$
  Show Answer
  The correct answer is B .
• Question 1510:

  The maximum electron in N shell is?

  Options:
  A) 2
  B) 8
  C) 18
  D) 32
  Show Answer
  The correct answer is D .