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 2121:

  Al₂O_3(s) + 3H₂SO_4(aq) → Al₂(SO_4(aq)) + 3H_2(I)O

  Al₂O_3(s) + 2NaOH_(aq)) + 3H_2(I)O → 2NaAl(OH)_4(aq)).

  We can conclude from the equations above that Al₂O_3(s) is?

  Options:
  A) an acidic oxide
  B) an amphoteric oxide
  C) a basic oxide
  D) a neutral oxide
  Show Answer
  The correct answer is B .
• Question 2122: Tin is unaffected by air at ordinary temperature due to its Options:
  A) Low melting point
  B) Weak electropositive character
  C) High boiling point
  D) White lustrous appearance
  Show Answer
  The correct answer is A .
• Question 2123: The brown fumes given off when trioxonitrate (V) acid is heated consist of ? Options:
  A) NO₂ and O₂
  B) H₂O and NO₂
  C) NO_2' O₂ and H₂O
  D) NO, NO₂ and H₂O
  Show Answer
  The correct answer is C .
• Question 2124:

  

  The diagram above is the solubility curve of a solute, X. Find the amount of X deposited when 500cm³ of a solution of X is cooled from 60^oC to 20^oC.

  Options:
  A) 0.750 mole
  B) 0.950 mole
  C) 2.375 moles
  D) 4.750 moles
  Show Answer
  The correct answer is A .
• Question 2125:

  Which of the following produces relatively few ions in solution?

  Options:
  A) NaOH
  B) Ca(OH)${}_2$
  C) KOH
  D) AI(OH)${}_3$
  Show Answer
  The correct answer is D .
• Question 2126:

  

  2HCL_(ag) + CaCO_3(ag) → CaCL_2(ag) + H₂O₍₁₎ + CO

  From the reaction above, which of the following curves represents the consumption of calcium trioxocarbonate (IV) as dilute HCL is added to it?

  Options:
  A) L
  B) M
  C) N
  D) P
  Show Answer
  The correct answer is B .
• Question 2127: How many structural isomers can be drawn for the non-cyclic alkanol with molecular formula C ₄H₁₀O? Options:
  A) 1
  B) 2
  C) 3
  D) 4
  Show Answer
  The correct answer is D .
• Question 2128:

  The shape of ammonia molecule is?

  Options:
  A) Trigonal planar
  B) Octahedral
  C) Square planar
  D) Tetrahedral
  Show Answer
  The correct answer is A .
• Question 2129:

  

  The IUPAC nomenclature for the compound above is

  Options:
  A) dimethlhexane
  B) 3,5 dimethylhexane
  C) 1.1 dmethyl, 3 methylpentane
  D) 2.4 dimethylhexane
  Show Answer
  The correct answer is D .
• Question 2130: An amphoteric oxide is an? Options:
  A) amorphous oxide of a metal
  B) amorphous oxide of a non-mental
  C) oxide that is insoluble in water
  D) oxide that behaves both as a base as well as an acid
  E) oxide that loses its oxygen on sublimation
  Show Answer
  The correct answer is D .