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 41: Which of the following statements is FALSE about isotopes of the same element? Options:
  A) They have the same number of electrons in their outermost shells
  B) They have different atomic masses
  C) They have the same atomic number and the number of electrons
  D) They have the same atomic number but different umber of elelctrons
  Show Answer
  The correct answer is D .
• Question 42: Addition of aqueous ammonia to a solution of Zn⁺⁺ gives a white precipitate which dissolves in an excess of ammonia because? Options:
  A) zinc is amphoteric
  B) zinc hydroxide is readily soluble
  C) zinc forms a complex which is readily soluble in excess ammonia
  D) ammonia solution is a strong base
  Show Answer
  The correct answer is C .
• Question 43: Bronze is preferred to copper in the making of medals because it Options:
  A) is stronger
  B) can withstand low temperature
  C) is lighter
  D) has low tensile strength
  Show Answer
  The correct answer is A .
• Question 44: A gas exerts pressure on its container because Options:
  A) the molecules of a gas collide with the walls of the container
  B) some of the molecules are moving faster than others
  C) of the collisions of the molecules with each other
  D) of the mass of the molecules of the gas
  Show Answer
  The correct answer is A .
• Question 45: An example of a neutral oxide is Options:
  A) AL₂O₃
  B) NO₂
  C) CO₂
  D) CO
  E) SO₂
  Show Answer
  The correct answer is D .
• Question 46: Air boiled out of water as steam is richer in Options:
  A) nitrogen and oxygen
  B) carbon (IV) oxide and oxygen
  C) noble gases and carbon (IV) oxide
  D) oxygen and noble gases
  Show Answer
  The correct answer is B .
• Question 47:

  N${}_2$O${}_4$⇔ 2NO${}_2$ ( = -ve)

  From the reaction above, which of these conditions would produce the highest equilibrium yield forN${}_2$O${}_4$?

  Options:
  A) Low temperature and high pressure
  B) Low temperature and low pressure
  C) high temperature and low pressure
  D) high temperature and high pressure
  Show Answer
  The correct answer is A .
• Question 48: A liquid that will dissolve fat is Options:
  A) hydrochloric acid
  B) calcium hydrochloride
  C) kerosene
  D) water
  Show Answer
  The correct answer is C .
• Question 49: In what respect will two dry samples of nitrogen gas differ from each other if sample 1 is prepared by completely removing CO₂ and O₂ from air, and sample 2 is prepared by passing purified nitrogen(i)oxide over heated copper? sample 1 is Options:
  A) purer than sample 2
  B) slightly denser than sample 2
  C) in all respects the same as sample 2
  D) colourless but sample 2 has a light brown colour
  E) slightly less reactive than sample 2
  Show Answer
  The correct answer is B .
• Question 50:

  Which important nitrogen-containing compound is produced in Haber's process?

  Options:
  A) NH${}_3$
  B) NO${}_2$
  C) NO
  D) HNO${}_3$
  Show Answer
  The correct answer is A .