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 1341:

  On which of the following is the solubility of a gaseous substance dependent? 

  I. Nature of solvent 

  II. Nature of solute 

  III. Temperature 

  IV. Pressure

  Options:
  A) I, II, III and IV
  B) I and II only
  C) II only
  D) I, III and IV only
  Show Answer
  The correct answer is D .
• Question 1342:

  

  Use the solubility curves below to answer questions. If 1 dm³ of a saturated solution of L at 60⁰C is cooled to 25⁰C, what amount in mole will separate out?

  Options:
  A) 0.75
  B) 0.25
  C) 1.00
  D) 0.50
  Show Answer
  The correct answer is A .
• Question 1343:

  Potassium trioxochlorate (V)has a solubility of 1.5 mol dm ^-3 at 45 ^oC.On cooling this solution to a temperature of 20 ^oC, the solubility was found to be 0.5 mol dm ^-3. What mass of KCIO ₃ was crystalized out?

  [K = 39, Cl = 35.5 O =16].

  Options:
  A) 1.00g
  B) 10.00g
  C) 12.25g
  D) 122.50g
  Show Answer
  The correct answer is D .
• Question 1344: If 48,000 coulombs of electricity are required to discharge 0.5 mole of sodium from a molten sodium chloride mass, then the number of coulombs required to discharge 2 moles of lead from molten lead (ll) chloride is? Options:
  A) 48,000
  B) 96,000
  C) 192,000
  D) 384,000
  E) 576,000
  Show Answer
  The correct answer is D .
• Question 1345: An increase in temperature causes an increase in the pressure of a gas because there is an increase in the? Options:
  A) average velocity of the molecules
  B) number of collisions between the molecules
  C) density of the molecules
  D) free mean path between each molecules and other
  Show Answer
  The correct answer is B .
• Question 1346: How many unpaired electron are in the p-orbitals of a fluorine atom? Options:
  A) 3
  B) $0$
  C) 1
  D) 2
  Show Answer
  The correct answer is C .
• Question 1347:

  

  In the diagram above, Y is a mixture of

  Options:
  A) calcium hydroxide and ammonium chloride
  B) calcuim hydroxide and sodium chloride
  C) sodium chloride and ammonuim trioxonitrate (V)
  D) sodium dioxonitrate (lll) and ammouium chloride
  Show Answer
  The correct answer is A .
• Question 1348: Which of the following substances is a basic salt? Options:
  A) Na₂CO₃
  B) Mg(OH)CI
  C) NaHCO₃
  D) KSO₄.AI₂(SO₄)₃,24H₂O
  Show Answer
  The correct answer is B .
• Question 1349:

  

  The IUPAC nomenclature of the compound above is

  Options:
  A) 2-ethylpentane
  B) 3,4-dimethylhexane
  C) 2,3-dimethylhexane
  D) 2-ethylhexane
  Show Answer
  The correct answer is B .
• Question 1350: What is the volume of oxygen required to burn complete 45 cm³ of methane at s.t.p? Options:
  A) 135.0 cm³
  B) 180.0 cm³
  C) 45.0 cm³
  D) 90.0 cm³
  Show Answer
  The correct answer is D .