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 261: Which one of the following metals is not normally extracted by chemical reduction because of its position in the electrochemical series? Options:
  A) Copper
  B) Iron
  C) Lead
  D) Potassium
  E) Zinc
  Show Answer
  The correct answer is D .
• Question 262: Detergents are manufacture with strength hydrocarbon chains is to make them Options:
  A) soluble
  B) biodegradable
  C) cheaper
  D) foamy
  Show Answer
  The correct answer is B .
• Question 263:

  Which of these alloys contains copper?

  Options:
  A) solder
  B) steel
  C) permallory
  D) bronze
  Show Answer
  The correct answer is D .
• Question 264: An example of oxidation - reduction enzyme is Options:
  A) amylase
  B) protease
  C) lipase
  D) dehydrogenase
  Show Answer
  The correct answer is D .
• Question 265: The reaction of halogens in the presence of sunlight is an example of Options:
  A) oxidation reaction
  B) addition reaction
  C) hydrogenation reaction
  D) substitution reaction
  Show Answer
  The correct answer is D .
• Question 266:

  At room temperature and standard pressure, chlorine gas is in which state of matter?

  Options:
  A) Plasma
  B) Solid
  C) Liquid
  D) Gas
  Show Answer
  The correct answer is D .
• Question 267: The solubility, in moles per dm³ of 20.2 g of potassium trioxonitrate (V) dissolve in 100 g of the resulting mixture is?(K = 39, O = 16, N =14). Options:
  A) 0.10
  B) 0.20
  C) 1.00
  D) 2.00
  Show Answer
  The correct answer is D .
• Question 268:

  Which of the following statements is true?

  Options:
  A) Metals conduct electricity while non-metals do not
  B) Metals have high density, non-metals have low density
  C) Metals form basic oxides, non-metals form acidic oxides
  D) In the electro chemical series, metals are above hydrogen while non-metals are below hydrogen
  E) Metals lose elections while non-metals gain electron during normal reactions
  Show Answer
  The correct answer is E .
• Question 269: (1 /(2) N_2(g) + (1) / (2)O_2(g) → NO_(g) ∆H° 89 KJ mol^-. If the entropy change for the reaction above at 25°C is 11.8 J mol^-, calculate the change in free energy. ∆G°, for the reaction at 25°C? Options:
  A) 88.71 KJ
  B) 85.48 KJ
  C) -204.00 KJ
  D) -3427.40 KJ
  Show Answer
  The correct answer is D .
• Question 270: Which of the following pairs of substance will react further with oxygen to form a higher oxide? Options:
  A) CO₂ and H₂O
  B) NO and H₂O
  C) CO and CO₂
  D) SO₂ and NO
  Show Answer
  The correct answer is D .