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 741: The radioactive emission with the least ionization power is Options:
  A) $\alpha -particles$
  B) X-rays
  C) $\gamma -rays$
  D) $\beta -rays$
  Show Answer
  The correct answer is C .
• Question 742:

  In a reaction: SnO + 2C → Sn + 2CO, the mass of coke containing 80% carbon required to reduce 0.302 kg of pure tin oxide is?

  (Sn - 119, O - 16, C - 12).

  Options:
  A) 0.40 kg
  B) 0.20 kg
  C) 0.06 kg
  D) 0.04 kg
  Show Answer
  The correct answer is C .
• Question 743: Tartaric acid is used industrially to Options:
  A) make baking powder
  B) make fruit juices
  C) remove rust
  D) dry substance
  Show Answer
  The correct answer is A .
• Question 744: Which of the following is found in cotton Options:
  A) Starch
  B) Cellulose
  C) Fat
  D) Oil
  Show Answer
  The correct answer is B .
• Question 745: 2CL^-_(aq) → CI_2(g) + 2e^-(aq). The above half-cell reaction occuring at the anode during the electrolysis of dilute ZnCI₂ solution is? Options:
  A) ionization
  B) oxidation
  C) reduction
  D) recombination
  Show Answer
  The correct answer is B .
• Question 746: In which of the following reactions can the oxidation number of the nitrogen be said to have increased? Options:
  A) 2NO_(g) + O_2(g) → 2NO_2(g)
  B) NO_(g) + Cl_2(g) → NOCl_2(l)
  C) FeSO_4(aq) + NO_(g) → Fe(NO)SO_4(s)
  D) NO_(g) + Br_2(l) → NOBr_2(l)
  Show Answer
  The correct answer is A .
• Question 747:

  A compound contains 40.0% carbon 6.7% hydrogen and 53.3% oxygen. If the molar mass of the compound is 180, find the molecular formula.

  [H = 1, C = 12, O = 16]

  Options:
  A) CH₂O
  B) C₃H₆O₃
  C) C₆H₁₂O₆
  D) C₆H₁₂O₃
  Show Answer
  The correct answer is C .
• Question 748: The most important use of hydrogen is in the Options:
  A) manufacture of ammonia
  B) manufacture of methyl alcohol
  C) manufacture of ethyl alcohol
  D) hydrogenation of oils
  Show Answer
  The correct answer is A .
• Question 749: Which of the noble gases has the greatest ionization energy Options:
  A) He
  B) Xe
  C) Ar
  D) Rr
  Show Answer
  The correct answer is A .
• Question 750: Hydrogen is not liberated when trioxonitrate(v)acid reacts with zinc because Options:
  A) zinx is not rendered passive by acid
  B) hydrogen produced is oxidized to water
  C) oxides of nitrogen are produced
  D) all nitrates are soluble in water
  E) trioxonitrate(v)acid is a strong acid
  Show Answer
  The correct answer is E .