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 1521:

  What mass of water is produced when 8.0g of hydrogen reacts with excess oxygen?

  [H = 1, O = 16]

  Options:
  A) 36.0g
  B) 8.0g
  C) 72.0g
  D) 16.0g
  Show Answer
  The correct answer is C .
• Question 1522:

  

  The acidic hydrogen in the compound is the hydrogen attached to carbon number

  Options:
  A) 5
  B) 4
  C) 3
  D) 1
  Show Answer
  The correct answer is D .
• Question 1523:

  

  Which of the five atoms can be described by the following properties: Relative atomic mass is greater than 30 but less than 40, it has odd atomic number and forms a unipositive ion in solution?

  Options:
  A) T
  B) W
  C) X
  D) Y
  E) Z
  Show Answer
  The correct answer is D .
• Question 1524: The greater the different in electronegativity between bonded atoms, the? Options:
  A) lower the polarity of the bond
  B) higher the polarity of the bond
  C) weaker the bond
  D) higher the possibility of the substance formed being a molecule
  Show Answer
  The correct answer is C .
• Question 1525:

  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 1526: The atomic number of caesium is 55 and its atomic mass is 133. The nucleus of caesium atom therefore contains Options:
  A) 78 protons and 55 elections
  B) 55 protons and 78 neutrons
  C) 55 neutrons 78 electrons
  D) 78 protons and 55 neutrons
  Show Answer
  The correct answer is B .
• Question 1527: A major process involved in the softening of hard water is the? Options:
  A) conversation of a soluble calcium salt to its trioxoncarbonate (lV)
  B) decomposition of calcium rioxocarbonate (lV)
  C) conversion of an insoluble calcium salts to its trioxocarbonate (lV)
  D) oxidation of calcium atoms to its ions
  Show Answer
  The correct answer is A .
• Question 1528: The principal constituent of natural gas is Options:
  A) methane
  B) ethane
  C) propane
  D) butane
  Show Answer
  The correct answer is A .
• Question 1529: Which of the following compounds will form a solution if exposed to air? Options:
  A) Na₂CO₃.10H₂O
  B) NaNO₃
  C) CuSO₄
  D) CaCl₂
  E) Na₂SO₄.10H₂O
  Show Answer
  The correct answer is D .
• Question 1530: If 30cm³ of oxygen diffuses through a porous pot in 7 seconds, how long will it take 60cm³ of chlorine to diffuse through the same pot, if the vapour densities of oxygen and chlorine are 16 and 36 respectively? Options:
  A) 9.3 sec
  B) 14 sec
  C) 21 sec
  D) 28 sec
  E) 30.3 sec
  Show Answer
  The correct answer is C .