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 681: How many moles of (H+) are there in 1 dm³ of 0.5 M solution of H₂SO₄? Options:
  A) 2.0 moles
  B) 1.0 moles
  C) 0.5 mole
  D) 0.25 mole
  Show Answer
  The correct answer is B .
• Question 682: The nucleus of the isotopes tritium contains Options:
  A) two neutrons with no protons
  B) one neutron and one proton
  C) two neutrons and one proton
  D) two neutrons, one proton and one electron
  Show Answer
  The correct answer is C .
• Question 683:

  An isotope has an atomic number of 15 and a mass number of 31. The number of protons it contains is

  Options:
  A) 16
  B) 15
  C) 46
  D) 31
  Show Answer
  The correct answer is B .
• Question 684:

  Soaps clean surfaces on the principlebased on?

  Options:
  A) viscosity
  B) floatation
  C) elasticity
  D) surface tension
  Show Answer
  The correct answer is D .
• Question 685:

  What is the mass percentage of carbon (C) in methane (CH4)? (The molar mass of carbon is approximately 12 g/mol.)

  Options:
  A) 25%
  B) 12%
  C) 75%
  D) 50%
  Show Answer
  The correct answer is C .
• Question 686:

  

  It can be deduced that the rate of the reaction

  Options:
  A) for bath l is higher than path ll
  B) for path ll is higher than path l
  C) is the same for both paths at all temperatures
  D) depends on the values of both x and y at all pressures
  Show Answer
  The correct answer is B .
• Question 687:

  What is the molar mass of water (H2O)?

  Options:
  A) 18 g/mol
  B) 22 g/mol
  C) 16 g/mol
  D) 12 g/mol
  Show Answer
  The correct answer is A .
• Question 688:

  Which of the following can be obtained by fractional distillation? 

  Options:
  A) Nitrogen from liquid air
  B) Sodium Chloride from sea water
  C) Iodine from solution of Iodine in carbon tetrachloride
  D) Sulphur from the solution of sulphur in carbon disulphide
  Show Answer
  The correct answer is A .
• Question 689: 2.0g of a monobasic acid was made up to 250 cm³ with distilled water. 25.00 cm³ of this solution required 20.00cm³ of 0.1 M NaOH solution for complete neutralization. The molar mass of the acid is? Options:
  A) 200 g
  B) 160 g
  C) 100 g
  D) 50 g
  Show Answer
  The correct answer is C .
• Question 690: Which of the following is not an alkali? Options:
  A) Ca(OH)₂
  B) NH₃
  C) NaOH
  D) Al(OH)₃
  Show Answer
  The correct answer is B .