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 951: A few drops of NaOH solution was added to an unknown salt forming a white precipitate which is insoluble in excess solution. The cation likely present is Options:
  A) Zn²⁺
  B) Pb²⁺
  C) Ca²⁺
  D) Al³⁺
  Show Answer
  The correct answer is C .
• Question 952:

  The emission of two successive beta particles from the nucleus ${}_{15}^{32}P$ will produce

  Options:
  A) ${}_{14}^{30}$Si
  B) ${}_{13}^{32}$Al
  C) ${}_{17}^{32}$Cl
  D) ${}_{16}^{32}$S
  Show Answer
  The correct answer is C .
• Question 953: The fundamental difference between the three states of matter is the Options:
  A) shape of their particles
  B) number of particles in each state
  C) shape of the container they occupy
  D) degree of movement of their particles
  Show Answer
  The correct answer is D .
• Question 954: A mixture of ethanol, sodium dichromate, and water is allowed to drop gradually into a boiling solution containing one part concentrated H₂SO
  ₄ and the liberate gas is collected by cooling it with ice water to give a liquid. This liquid is? Options:
  A) ethanoic acid
  B) acetaldehyde
  C) ethyl acetate
  D) methanol
  E) ethylene
  Show Answer
  The correct answer is A .
• Question 955: When sodium hydroxide is heated with ammonium tetraoxosulphate (IV), the gas given off may be collected by? Options:
  A) bubbling it through concentrated H₂SO₂
  B) bubbling it through water and then passing it through calcium oxide
  C) passing it directly through calcium oxide
  D) passing it directly through calcium chloride
  Show Answer
  The correct answer is C .
• Question 956: An isomer of C₅H₁₂ is Options:
  A) Butane
  B) 2 – methylbutane
  C) 2 – methylpropane
  D) 2 – ethylbutane
  Show Answer
  The correct answer is B .
• Question 957:

  The situation obtained when a perfect gas expands into a vacuum is

  Options:
  A) ΔH is positive and TΔ S is zero
  B) ΔH is positive and T Δ S is negative
  C) ΔH is negative and TΔ S is zero
  D) ΔH is zero and T Δ S is positive
  Show Answer
  The correct answer is D .
• Question 958: The chemicals used to soften hard water involves the addition of Options:
  A) insoluble sodium compounds which from soluble solutions of calcium and magesium
  B) solube soudium compounds which from soluble solutions of calcium and magnesium ions
  C) solube sodium compounds which from insoluble precipitates of calcium and magnesium ions
  D) insoluble precipitates of calcium and magnesium ions
  Show Answer
  The correct answer is C .
• Question 959: Deliquescent substances are also? Options:
  A) efflorescent
  B) anhydrous
  C) hygroscopic
  D) insoluble
  Show Answer
  The correct answer is C .
• Question 960:

  

  Use the solubility curves below to answer questions. If 1 dm³ of a saturated solution of L at 60⁰C is cooled to 25⁰C, what amount in mole will separate out?

  Options:
  A) 0.75
  B) 0.25
  C) 1.00
  D) 0.50
  Show Answer
  The correct answer is A .