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 1321: C₃H_8(g) + 50_2(g) → 4H₂O + 3CO_2(g). Form the equation above the volume of oxygen at s.t.p. required to burn 50cm³ of propane is? Options:
  A) 250 cm³
  B) 150 cm³
  C) 100 cm ³
  D) 50 cm³
  Show Answer
  The correct answer is A .
• Question 1322: The removal of rust from iron by treatment with tetraoxosulphate (IV) acid is based on the? Options:
  A) hydrolysis of the iron
  B) reaction of acid with base
  C) oxidationof the rust
  D) dehydration of the iron
  Show Answer
  The correct answer is D .
• Question 1323: A side effect of soft water is that Options:
  A) it gives offensive taste
  B) excess calcium is precipitated
  C) it attcaks lead contained in pipes
  D) it encourages the growth of bacteria
  Show Answer
  The correct answer is C .
• Question 1324:

  If the molecular mass of tetraoxosulphate (VI) acid is 98, calculate its vapour density.

  Options:
  A) 196
  B) 49
  C) 106
  D) 82
  Show Answer
  The correct answer is B .
• Question 1325:

  

  In the diagram above, gas X is

  Options:
  A) hydrogen
  B) chlorine
  C) oxygen
  D) hydrogen chloride
  Show Answer
  The correct answer is C .
• Question 1326: If the silver mirror test is positive, it indicates the presence of an Options:
  A) alkyne
  B) alkanol
  C) alkanone
  D) alkanal
  Show Answer
  The correct answer is D .
• Question 1327: A mixture of 0.20 mole of Ar, 0.20 mole of N₂ and 0.30 mole of He exerts a total pressure of 2.1 atm. The partial pressure of He in the mixture is? Options:
  A) 0.90 atm
  B) 0.80 atm
  C) 0.70 atm
  D) 0.60 atm
  Show Answer
  The correct answer is A .
• Question 1328: Which of the following elements will form oxide which will dissolve both in dilute HNO₃ and NaOH solutions to form salts? Options:
  A) Al
  B) Mg
  C) Ag
  D) Mn
  Show Answer
  The correct answer is A .
• Question 1329: The major and most effective way of controlling pollution is to Options:
  A) improve machinery so that the substances released from combustion are less harmful
  B) pass strict laws against it by individuals and companies
  C) educate people on the causes and effects of pollution
  D) convert chemical wastes to harmless substances before releasing them into the environment
  Show Answer
  The correct answer is C .
• Question 1330:

  

  Z in diagram above represents

  Options:
  A) heat of reaction
  B) activation energy
  C) free energy
  D) entropy of reaction
  Show Answer
  The correct answer is A .