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 911: The oxidation number of boron in NaBH ₄ is Options:
  A) -3
  B) -1
  C) +1
  D) +3
  Show Answer
  The correct answer is D .
• Question 912:

  

  The compound above is an

  Options:
  A) alkanone
  B) alkanoate
  C) alkanal
  D) akanol
  Show Answer
  The correct answer is A .
• Question 913: 20 cm³ of 1.0 molar NH₄OH solution when neutralized with 20.05cm³ of 0.1 molar HCl liberated -102 joules of heat. Calculate the heat of neutralization of NH₄OH? Options:
  A) -51.O KJ mol^-
  B) +57.3 KJ mol^-
  C) +57.O KJ mol^-
  D) +51.0 KJ mol^-
  Show Answer
  The correct answer is A .
• Question 914: 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 915:

  The nucleusof a hydrogen atom consist of a?

  Options:
  A) 1 proton only
  B) 1 proton, 2 neutron
  C) 1 neutron only
  D) 1 electron only
  Show Answer
  The correct answer is A .
• Question 916:

  The lanthanides and actinides are located in which block of the periodic table?

  Options:
  A) P-block
  B) S-block
  C) F-block
  D) D-block
  Show Answer
  The correct answer is C .
• Question 917:

  A dense white fume is formed when ammonia gas reacts with

  Options:
  A) O_2(g)
  B) H_2(g)
  C) Cl_2(g)
  D) HCl_(g)
  Show Answer
  The correct answer is D .
• Question 918: Which of the following processes NOT lead to a chemical change? Options:
  A) Strirring iron in sulphur (IV) acid
  B) Stirring sodium carbonate in water
  C) Stirring glucose in concentrated sulphur (IV) acid
  D) Mixing sulphur (IV) acid with potassium carbonate
  E) Titrating an acid against base
  Show Answer
  The correct answer is B .
• Question 919:

  Which of the following factors does NOT affect the rate of a chemical reaction?

  Options:
  A) Concentration of reactants
  B) Presence of a catalyst
  C) Molecular weight of products
  D) Temperature
  Show Answer
  The correct answer is C .
• Question 920: What is the valence shell electron configuration of the element with atomic number 17? Options:
  A) 1s² 2s² 2p⁶ 3s² 3p⁴
  B) 1s² 2s² 2p⁶ 3s² 3p⁵
  C) 2s² 2p⁶
  D) 3s² 3p⁵
  Show Answer
  The correct answer is B .