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 71: On which of the following is the solubility of a gaseous substance dependent? I. Nature of solvent II. Nature of solute III. Temperature IV. Pressure Options:
  A) I, II, III and IV
  B) I and II only
  C) II only
  D) I, III and IV only
  Show Answer
  The correct answer is D .
• Question 72: At 25^oC and 1atm, a gas occupies a volume of 1.50dm³. What volume will it occupy at 100^oC and 1atm? Options:
  A) 1.88 dm³
  B) 6.00 dm³
  C) 18.80 dm³
  D) 18.80 dm³
  E) 60.00dm³
  Show Answer
  The correct answer is A .
• Question 73:

  The mass number of a nucleus is?

  Options:
  A) Always less than its atomic number
  B) The sum of the number of protons and neutrons present in the nucleus
  C) Always more than the atomic weight
  D) A fraction
  Show Answer
  The correct answer is B .
• Question 74: If glucose is heated on the concentration tetraoxosulphate(iv)acid, it will be dehydrated Options:
  A) carbon
  B) carbon(iv)oxide
  C) ethane
  D) ethanol
  Show Answer
  The correct answer is A .
• Question 75: Which of the following compounds can be represented by the molecular formula C2 H6O? Options:
  A) propanal
  B) ethanol
  C) methanoic acid
  D) glucose
  Show Answer
  The correct answer is B .
• Question 76: The mixture of gases used in a photographer's flash tube is Options:
  A) argon and krypton
  B) krypton and xenon
  C) helium and argon
  D) argon and xenon
  Show Answer
  The correct answer is B .
• Question 77: When ΔH is negative, a reaction is said to be Options:
  A) endothermic
  B) exothermic
  C) reversible
  D) ionic
  Show Answer
  The correct answer is B .
• Question 78:

  When water drops are added to calcium carbide in a container and the gas produced is passed through a jet and lighted, the resultant flame is called an?

  Options:
  A) Oxyethene
  B) Oxyhydrocarbon flame
  C) Oxyacetylene flame
  D) Oxymethane flame
  Show Answer
  The correct answer is C .
• Question 79: A common characteristic between zinc and the other transition elements is the ability to Options:
  A) have variable oxidation states
  B) from complex ions
  C) act as a catalyst
  D) from coloured ions
  Show Answer
  The correct answer is B .
• Question 80: The rate of diffusion of a gas Y is twice that of Z If the relative molecular mass of Y is 64 and the two gases diffuse under the same conditions, find the relative molecular mass of Z Options:
  A) 32
  B) 4
  C) 8
  D) 16
  Show Answer
  The correct answer is D .