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 2181:

  In the laboratory preparation of oxygen, the gas cannot be collected by displacement of air because

  Options:
  A) the density of oxygen is greater than that of air
  B) the density of air is nearly the same as that of oxygen
  C) oxygen is a component of air
  D) air is an impure substance
  Show Answer
  The correct answer is A .
• Question 2182: Calculate the volume of carbon (IV)oxide measured at s.t.p, produced when 1 kg of potassium hydrogen trioxocarbonate (IV) is totally decomposed by heat?(G.M.V. at s.t.p 22.4 dm³, K = 39, O = 16, C = 12, H = 1) Options:
  A) 28 dm³
  B) 56 dm³
  C) 112 dm³
  D) 196 dm³
  Show Answer
  The correct answer is C .
• Question 2183: 28.8 cm³ of nitrogen at 15°C is cooled to O°C at constant pressure, the new volume of nitrogen is? Options:
  A) 17.4 cm³
  B) 14.7 cm³
  C) 27.3 cm³
  D) 31.7 cm³
  Show Answer
  The correct answer is C .
• Question 2184:

  Which of the following is a common property of non-metals?

  Options:
  A) Exist as solids at room temperature
  B) Tend to gain electrons in chemical reactions
  C) High thermal conductivity
  D) Readily form cations in chemical reactions
  Show Answer
  The correct answer is B .
• Question 2185:

  

  In the diagram above, mixture Y is

  Options:
  A) NH₄NO_3(s) + CaSO_4(s),/sub>
  B) NH₄CL_(s) + NaNO_2(s)
  C) NH₄NO_2(s) + Na₂SO_4(s)
  D) NH₄CL_(s) + Ca(OH)_2(s)
  Show Answer
  The correct answer is D .
• Question 2186: The mixture of gases used in a photographer's flash tube is Options:
  A) argon and krypton
  B) krypton and xenon
  C) helium and argon
  D) argon and xenon
  Show Answer
  The correct answer is B .
• Question 2187: The salt formed from a reaction between citric acid and sodium hydroxide in solution will be Options:
  A) acidic
  B) basic
  C) complex
  D) neutral
  Show Answer
  The correct answer is B .
• Question 2188:

  

  The diagram above represents the formation of

  Options:
  A) a metallic bond
  B) an electrovalent bond
  C) a covalent bond
  D) a coordinate covalent bond
  Show Answer
  The correct answer is C .
• Question 2189: During the vulcanization of rubber, sulphur is added to Options:
  A) Break down rubber polymer
  B) Lengthen the chain of rubber
  C) Bind rubber molecules together
  D) Act as a catalyst
  Show Answer
  The correct answer is C .
• Question 2190:

  

  The IUPAC name of the compound above is
  Options:
  A) 2,2-dimethyl but -1-yne
  B) 2,2-dmethyl but -1-ene
  C) 3,3-dimethyl but -1-ene
  D) 3,3-dimethyl but-1-yne
  Show Answer
  The correct answer is C .