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 1521: How many unpaired electron(s) are there in the nitrogen sub-levels/ Options:
  A) 3
  B) 2
  C) 1
  D) none
  Show Answer
  The correct answer is A .
• Question 1522:

  The constituent common to duralumin and alnico is

  Options:
  A) Co
  B) Mn
  C) Al
  D) Mg
  Show Answer
  The correct answer is C .
• Question 1523: If the elements X and Y have atomic numbers 11 and 17 respectively, what type of bond can they form? Options:
  A) Dative
  B) Covalent
  C) Lonic
  D) Metallic
  Show Answer
  The correct answer is C .
• Question 1524: 2H₂S_(g) + SO_2(g) → 3S_(s) + 2H₂O_(I). The above reaction is? Options:
  A) a redox reaction H₂S is the oxidant and SO₂ is the reductant
  B) a redox reaction in which SO₂ is the oxidant and H₂S is the reductant
  C) not a redox reaction because there is no oxidant in reaction equation
  D) not a redox because there is no reductant in the reaction equation
  Show Answer
  The correct answer is B .
• Question 1525: The substance least considered as a source of environmental pollution is Options:
  A) Lead compounds
  B) Organophosphorous compounds
  C) Silicate minerals
  D) Uranium
  Show Answer
  The correct answer is C .
• Question 1526: A decrease in atomic size and an increase in nuclear charge across a period lead to Options:
  A) an increase in the tendency to lose electron
  B) an increase in chemical reactivity
  C) a decrease in electropositivity
  D) a decrease in covalency in bond formation
  Show Answer
  The correct answer is B .
• Question 1527: A constituent common to bronze and solder is Options:
  A) lead
  B) silver
  C) copper
  D) tin
  Show Answer
  The correct answer is D .
• Question 1528: An increase in temperature causes an increase in pressure of a gas in a fixed volume due to an increase in the? Options:
  A) number of molecules of the gas
  B) density of the gas molecules
  C) number of collisions between the gas molecules
  D) number of collisions between the gas molecules and the walls of the container
  Show Answer
  The correct answer is D .
• Question 1529:

  The fourteen elements (atomic number 90-103) after actinium are called?

  Options:
  A) Actinoids
  B) Nucleotides
  C) Pre-actinum elements
  D) Atomic elements
  Show Answer
  The correct answer is A .
• Question 1530: Which of the following is NOT involved in the extraction of metals from their ores? Options:
  A) reduction with carbon
  B) reduction with other metals
  C) reduction by electrolysis
  D) oxidation with oxidizing agents
  Show Answer
  The correct answer is D .