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 251: 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 252:

  To what volume must 300cm${}^3$ of 0.60M sodium hydroxide solution be diluted to give a 0.40M solution?

  Options:
  A) 450cm${}^3$
  B) 300cm${}^3$
  C) 200cm${}^3$
  D) 150cm${}^3$
  Show Answer
  The correct answer is A .
• Question 253: Which of the following metals is the least reactive? Options:
  A) Pb
  B) Sn
  C) Hg
  D) Au
  Show Answer
  The correct answer is D .
• Question 254:

  The nucleus of an atom consists of?

  Options:
  A) Electrons and neutrons
  B) Electrons and protons
  C) Protons and neutrons
  D) None of the above
  Show Answer
  The correct answer is C .
• Question 255: The reaction between hydrogen and iodine may be represented by the equation H₂(g)+ I₂(g) → 2HI(g), and is exothermic. Therefore Options:
  A) an increase in temperature favours the forword reaction
  B) an increase in pressure favours the backward reaction
  C) both pressure and temperature muct be increased to favour the forward reaction
  D) a decrease in temperature will favour the forward reaction
  E) a decrease in pressure and an increase in temperature will favour the forward reaction
  Show Answer
  The correct answer is D .
• Question 256:

  The type of bonding in [Cu(NH${}_3$)${}^4$]${}^{2+}$ is 

  Options:
  A) coordinate
  B) electrovalent
  C) metallic
  D) covalent
  Show Answer
  The correct answer is A .
• Question 257:

  Which of the following methods can be used to remove temporary hardness from water?

  Options:
  A) Boiling
  B) Filtration
  C) sedimentation
  D) Chlorination
  Show Answer
  The correct answer is A .
• Question 258: The equilibrium of an endothermic reaction which proceeds with an increase in volume can be shifted in the reverse direction by Options:
  A) increasing the temperature and decreasing the pressure
  B) increasing the pressure and increasing the temperature
  C) decreasing the temperature and increasing the pressure
  D) decreasing the pressure and decreasing the temperature
  Show Answer
  The correct answer is C .
• Question 259:

  What unit of temperature should be used when applying the ideal gas law?

  Options:
  A) Fahrenheit (°F)
  B) Kelvin (K)
  C) Rankine (°R)
  D) Celsius (°C)
  Show Answer
  The correct answer is B .
• Question 260: What volume of 0.5mldm³ H₂SO₄ will exactly neutralize 20cm³ of 0.1moldm³ NaOH Solution? Options:
  A) 2.0cm³
  B) 5.0cm³
  C) 6.8cm³
  D) 8.3cm³
  Show Answer
  The correct answer is A .