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 801: Bronze is an alloy of? Options:
  A) silver and copper
  B) silver and gold
  C) copper and nickle
  D) copper and zinc
  E) copper and tin
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  The correct answer is E .
• Question 802: What is the IUPAC nomenclature of the compound NaCIO? Options:
  A) sodium oxochlorate (I)
  B) sodium chloro (I) oxide
  C) sodium monooxochlorate (II)
  D) sodium chloro (I) monoxide
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  The correct answer is A .
• Question 803:

  The two ions responsible for hardness in water are

  Options:
  A) Ca${}^{2+}$ and / or Mg${}^{2+}$
  B) K${}^{+}$ and / or Mg${}^{2+}$
  C) Ca${}^{2+}$ and / or Li${}^{+}$
  D) Ca${}^{2+}$ and / or Na${}^{+}$
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  The correct answer is A .
• Question 804: Which of the following are isomers? Options:
  A) Ethanol and dimethyl ether
  B) Benzene and methybenzene
  C) Ethanol and propanone
  D) Trichloromethane and tetrachloromethane
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  The correct answer is A .
• Question 805: In the laboratory preparation of oxygen, dried oxygen is usually collected over Options:
  A) hydrochloric acid
  B) mercury
  C) calcium chloride
  D) tetraoxosulphate (VI) acid
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  The correct answer is B .
• Question 806: An endothermic reaction is one during which heat is.....and can be represented by the symbol.... which of the following combinations can be used accurately to complete the above definition? Options:
  A) liberated, -$\mathrm{\Delta }$H
  B) liberated, +$\mathrm{\Delta }$H
  C) absorbed, -$\mathrm{\Delta }$H
  D) absorbed, +$\mathrm{\Delta }$H
  E) absorbed, +$\mathrm{\Delta }$G
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  The correct answer is D .
• Question 807:

  The reactions below represent neutralization reaction, in which of them is the value of H highest?

  Options:
  A) CH${}_3$CH${}_2$COOH + KOH → CH${}_3$CH${}_2$COOK + H${}_2$O
  B) NH${}_4$OH + HCL → NH${}_4$ + H${}_2$O
  C) NaOH + HCL → NaCL + H${}_2$O
  D) CH${}_3$COOH + NaOH → CH${}_3$COONa + H${}_2$O
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  The correct answer is C .
• Question 808: How many structural isomers can be written for the alkyl bromide, C₄H₉Br? Options:
  A) 3
  B) 4
  C) 6
  D) 8
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  The correct answer is B .
• Question 809: Due to the high reactivity of sodium, it is usually stored under Options:
  A) water
  B) mercury
  C) paraffin
  D) phenol
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  The correct answer is C .
• Question 810: 30cm³ of hydrogen was collected over water at 27°C and 780 mm Hg. If the vapour pressure of water at the temperature of the experiment was 10 mm Hg, calculate the volume of the gas at 760 mm Hg and 7°C? Options:
  A) 40.0 cm³
  B) 35.7 cm³
  C) 28.4 cm³
  D) 25.2 cm³
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  The correct answer is C .