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 551: The correct order of increasing oxidation number of the transition metal ions for the compounds K₂Cr₂O₇, V₂O₅ and KMnO₄ is Options:
  A) V₂O₅< K_2Cr2O₇< KMnO₄
  B) K₂Cr₂O₇< KMnO_{4 < V2O5}
  C) KMnO₄< K_2Cr2O₇< V_2O5
  D) KMnO₄< V_2O5< K_2Cr2O₇
  Show Answer
  The correct answer is A .
• Question 552: If 24.83 cm³ of 0.15 M NaOH is titrated to its end point with 39.45 cm³ of HCl, what is the molarity of the HCl? Options:
  A) 0.094 M
  B) 0.150 M
  C) 0.940 M
  D) 1.500 M
  Show Answer
  The correct answer is A .
• Question 553: Due to the high reactivity of sodium, it is usually stored under Options:
  A) water
  B) mercury
  C) paraffin
  D) phenol
  Show Answer
  The correct answer is C .
• Question 554: The experiment that showed that atoms have tiny positively charged nucleus was first carried out by Options:
  A) Moseley
  B) Rutherford
  C) Millikan
  D) Dalton
  Show Answer
  The correct answer is B .
• Question 555:

  

  In the diagram above , the activation energy for the backward reaction is

  Options:
  A) +5kJ
  B) +15KJ
  C) +25KJ
  D) +30KJ
  Show Answer
  The correct answer is C .
• Question 556: The minimum volume of oxygen required for the complete combustion of a mixture of 10cm ³ of CO and 15 cm ³ of H ² is Options:
  A) 25.0cm³
  B) 12.5 cm³
  C) 10.0 cm³
  D) 5.0cm³
  Show Answer
  The correct answer is C .
• Question 557: Environmental pollution is worsened by the release from automobile exhausts of Options:
  A) Water vapour
  B) Steam
  C) Smoke
  D) Heavy metals
  Show Answer
  The correct answer is C .
• Question 558: When sodium ethanoate is treated with a few drops of concentrated tetraoxosulphate(vi)acid. one of the products is Options:
  A) CH₃COOH
  B) CH₃COOCH₃
  C) CH₃COOC₂H₅
  D) C₂H₅COOCH₃
  Show Answer
  The correct answer is A .
• Question 559: Which of the following gases can be collected by the method of downward delivery? Options:
  A) Chlorine
  B) Oxygen
  C) Ammonia
  D) Hydrogen
  Show Answer
  The correct answer is A .
• Question 560: How many grams of bromine will be required to completely react with 10 g of propyne?(C = 12, H = 1, Br = 80) Options:
  A) 20 g
  B) 40 g
  C) 60 g
  D) 80 g
  Show Answer
  The correct answer is D .