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 461: The function of sulphur during vulcanization rubber is to? Options:
  A) act as catalyst for the polymerization of rubber molecules
  B) convert rubber from thermosetting to thermo plastics polymer
  C) from chains which bind rubber molecules together
  D) break down rubber polyer
  E) shorten the chain length of rubber polyer
  Show Answer
  The correct answer is C .
• Question 462:

  A few drop of conc HCL are added to about 10cm${}^3$ of a solution of PH 3.4. The PH of the resulting mixture is?

  Options:
  A) less than 3.4
  B) greater than 3.4
  C) unaltered
  D) the same as that of the pure water
  Show Answer
  The correct answer is A .
• Question 463: An oxide XO₂ has a vapour density of 32. What is the atomic mass of X? Options:
  A) 20
  B) 32
  C) 14
  D) 12
  Show Answer
  The correct answer is B .
• Question 464:

  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 465: which of the following polymers is suitable for packaging and electrical insulation? Options:
  A) polyamide
  B) polyethene
  C) polycarbonate
  D) polystyrene
  Show Answer
  The correct answer is D .
• Question 466:

  The hydrogen ion concentration of a sample of orange juice is $2.0\times {10}^{-11}$ moldm${}^{-3}$. What is its p${}^{\text{OH}}$? $\log {10}^2=0.3010$

  Options:
  A) 3.30
  B) 13.00
  C) 10.70
  D) 11.30
  Show Answer
  The correct answer is A .
• Question 467: 90.0g of MgCI₂ was placed in 50.0cm³ of water to give a saturated solubility of the salt is 8.0 mol dm³ at the same temperature, what is the mass of the salt left undissolved at the given temperature?(Mg = 24, Cl = 35.5) Options:
  A) 52.0g
  B) 58.5g
  C) 85.5g
  D) 88.5g
  Show Answer
  The correct answer is A .
• Question 468: In the reaction of oxygen with hydrogen to produce water, which of the following statements is true? Options:
  A) One atom of hydrogen reacts with two atoms of oxygen to give one molecule of water
  B) Two atoms of hydrogen react with two atoms of oxygen to give two molecules of water
  C) One molecule of oxygen reacts with one molecule of hydrogen to give two molecules of water
  D) One molecule of hydrogen reaccts with two molecules of oxygen to give three molecules of water
  E) One molecule of oxygen reacts with two molecules of hydrogen to give two molecules of water
  Show Answer
  The correct answer is E .
• Question 469: The reaction of an alkanol with an alkanoic acid in the presence of concentrated H₂SO₄ will produce an? Options:
  A) alkanal
  B) alkanoate
  C) alkanone
  D) alkyne
  Show Answer
  The correct answer is B .
• Question 470:

  The dehydration of CH${}_3$CH${}_2$CH${}_2$CH${}_2$OH will give?

  Options:
  A) HC≡CCH${}_2$CH${}_3$
  B) CH${}_2$≡CH${}_2$CH${}_3$
  C) CH${}_3$C≡CCH${}_3$
  D) CH${}_3$CH=CHCH${}_3$
  Show Answer
  The correct answer is D .