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 361:

  What unit of temperature should be used when applying the ideal gas law?

  Options:
  A) Fahrenheit (°F)
  B) Kelvin (K)
  C) Rankine (°R)
  D) Celsius (°C)
  Show Answer
  The correct answer is B .
• Question 362:

  Which of the following could not be alkane?

  Options:
  A) C${}_4$H${}_{10}$
  B) C${}_5$H${}_{12}$
  C) C${}_7$H${}_{14}$
  D) C${}_8$H${}_{18}$
  Show Answer
  The correct answer is C .
• Question 363: A red precipitate of copper (I) carbide is formed when ammonium solution of copper (I) chloride is introduced into Options:
  A) CH₃CH₂CH₂CH₃
  B) CH₂ = CH - CH₂CH₃
  C) CH₃CH₂ - C = CH
  D) CH₃ - C = C - CH₃
  Show Answer
  The correct answer is C .
• Question 364: C_xH_Y + 4O₂ → 3CO₂ + 2H₂O. The hydrocarbon, C_xH_Y, in the reaction above is? Options:
  A) propane
  B) propene
  C) propyne
  D) propanone
  Show Answer
  The correct answer is C .
• Question 365: Increasing the pressure of a gas Options:
  A) lowers the average kinetic energy of the molecules
  B) decreases the density of the gas
  C) decreases the temperature of the gas
  D) increases the density of the gas
  E) increases the volume of the gas
  Show Answer
  The correct answer is D .
• Question 366: When cathode rays are deflected onto the electrode of an electrometer, the instrument becomes Options:
  A) negatively charged
  B) positvely charged
  C) neutral
  D) bipolar
  Show Answer
  The correct answer is A .
• Question 367: A hydrocarbon has an empirical formula CH and a vapour density of 39. Determine its molecular formula.[C = 12, H = 1] Options:
  A) C₂H₆
  B) C₃H₈
  C) C₃H₄
  D) C₆H₆
  Show Answer
  The correct answer is D .
• Question 368: 50 cm³ of gas was collected over water at 10^oC and 765 mm Hg. Calculate the volume of the gas at s.t.p. if the saturated vapour pressure of water at 10 ^oC is 5mm Hg Options:
  A) 49.19 cm ³
  B) 48.87 cm ³
  C) 48.55 cm ³
  D) 48.23 cm ³
  Show Answer
  The correct answer is D .
• Question 369: What properties of duralumin make it more useful than its constituent metals? Options:
  A) It is heavy with a high melting point
  B) It is malleable and has high density
  C) It is strong and light
  D) It is hard and ductile
  Show Answer
  The correct answer is C .
• Question 370:

  What is the mass (in grams) of 500 mL of ethanol? (density of ethanol = 0.789 g/mL)

  Options:
  A) 394.5 mL
  B) 500 mL
  C) 394.5 g
  D) 500 g
  Show Answer
  The correct answer is C .