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 51: 0.07g of a hydride of carbon occupies 56.0cm³ at S.T.P. when vaporized and contains 14.29% by mass of hydrocarbon is(C = 12, H = 1) Options:
  A) CH₄
  B) C₂H₂
  C) C₂H₄
  D) C₂H₆
  E) C₃H₈
  Show Answer
  The correct answer is C .
• Question 52: An element, Z froms an anion whose formula is [Z(CN)₆]^y. If Z has an oxidation number of +2, what is the value of y? Options:
  A) - 2
  B) - 3
  C) - 4
  D) - 5
  Show Answer
  The correct answer is C .
• Question 53: When sodium trioxocarbonate (IV) decahydrate loses its water of crystallization to the atmosphere, the process is Options:
  A) deliquescence
  B) efflorescence
  C) hygroscopic
  D) effervesecence
  Show Answer
  The correct answer is B .
• Question 54: Fats and oils are? Options:
  A) addition products of long chain fatty acids and alkali
  B) addition products of long-chain fattyy acids and glycerol
  C) condensation products of long-chain fatty acids and glycerol
  D) condensation products of formaldehyde and glycerol
  E) liquids at 20°C
  Show Answer
  The correct answer is C .
• Question 55: Which of the following statement is true of a proton? Options:
  A) The mass of a proton is 1840 times the mass of electron
  B) the total mass of the protons in a particular nucleus is always half the nuclear size
  C) The mass of a proton is one - twelfth the molar mass of carbon
  D) The mass of a proton is 1.0008g
  Show Answer
  The correct answer is D .
• Question 56:

  For the general equation of the nature

  XP + yQ ⇌ mR + nS, the expression for the equilibrium constant is

  Options:
  A) k[P]${}^x$[Q]${}^y$
  B) $\frac{m[R][S]}{x[P]y[Q]}$
  C) $\frac{[P{]}^x[Q{]}^y}{[R{]}^m[S{]}^n}$
  D) $\frac{[R{]}^m[S{]}^n}{[P{]}^x[Q{]}^y}$
  Show Answer
  The correct answer is D .
• Question 57:

  Which of the following mixtures is an example of a colloid?

  Options:
  A) Milk
  B) Orange juice
  C) Saltwater
  D) Sugar dissolved in water
  Show Answer
  The correct answer is A .
• Question 58:

  What quantity of electricity will liberate 0.125 mole of oxygen molecules during the electrolysis of dilute sodium chloride solution?

  [ F = 96 5000 C mol^-1 ]

  Options:
  A) 24 125 coulombs
  B) 48 250 coulombs
  C) 72 375 coulombs
  D) 96 500 coulombs
  Show Answer
  The correct answer is B .
• Question 59: Hydrogen is used in oxy-hydrogen flames for melting metals because it Options:
  A) evolves a lot of heat when burnt
  B) combines explosively with oxygen
  C) is a very light gas
  D) is a rocket fuel
  Show Answer
  The correct answer is A .
• Question 60:

  A solution X, on mixing with AgNO${}_3$ solution gives a white precipitate soluble in aqueous NH${}_3$, a solution Y, when also added to X, also gives a white precipitate which is soluble when heated solutions X and Y respectively contain

  Options:
  A) Al${}^{3+}$, Cl${}^{-}$
  B) Hg${}^{+}$, SO${}_4^{2-}$
  C) Pb${}^{2+}$, Cl${}^{-}$
  D) Ag${}^{+}$, SO${}_4^{2-}$
  Show Answer
  The correct answer is C .