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 31:

  The molar enthalpy change accompanying the removal of an electron from a gas phase atom orion in its ground state is called?

  Options:
  A) Electron gain enthalpy
  B) Ionization enthalpy
  C) Enthalpy change
  D) Enthalpic gas removal
  Show Answer
  The correct answer is B .
• Question 32: 0.07g of a hydride of carbon occupies 56.0cm³ at S.T.P. when vaporized and contains 14.29% by mass of hydrocarbon is(C = 12, H = 1) Options:
  A) CH₄
  B) C₂H₂
  C) C₂H₄
  D) C₂H₆
  E) C₃H₈
  Show Answer
  The correct answer is C .
• Question 33:

  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 34: Fermentation is the Options:
  A) breaking down of carbohydrate to glucose
  B) conversion of sugar to alcohol in the presence of yeast
  C) breaking down of sugar to carbohydrate
  D) conversion of alcohol to sugar in the presence of yeast
  Show Answer
  The correct answer is B .
• Question 35: The principle of column chromatography is based on th ability of the constituents to Options:
  A) React with the solvent in the column
  B) React with each other in the solvent in the column
  C) Dissolve in each other in the column
  D) Move at different speeds in the column
  Show Answer
  The correct answer is D .
• Question 36:

  What is the maximum number of electrons that can occupy the second energy level (n=2)?

  Options:
  A) 2 electrons
  B) 18 electrons
  C) 8 electrons
  D) 32 electrons
  Show Answer
  The correct answer is C .
• Question 37: Crude petroleum pollutant usually seen on some Nigerian creeks and waterways can be dispersed or removed by Options:
  A) heating the affected parts in order to boil off the petroleum
  B) mechanically stirring to dissolve the petroleum in water
  C) pouring organic solvents to dissolve the petroleum
  D) spraying the water with stergents
  E) cooling to freeze out the petroleum
  Show Answer
  The correct answer is C .
• Question 38: Carbon (II) oxide is considered dangerous if inhaled mainly because it Options:
  A) can cause injury to the nervous system
  B) competes with oxygen in the blood
  C) competes with carbon (IV) oxide in the blood
  D) can cause lung cancer
  Show Answer
  The correct answer is B .
• Question 39: Which of the following is a physical change? Options:
  A) The bubbling of chlorine into water
  B) The bubbling of chlorine into a jar contanining hydrogen
  C) The dissolution of sodium chloride in water
  D) The passing of steam over heated iron
  Show Answer
  The correct answer is C .
• Question 40: The principal constituent of natural gas is Options:
  A) methane
  B) ethane
  C) propane
  D) Butane
  Show Answer
  The correct answer is A .