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 121:

  Which of the following statements does not show Rutherford's account of Nuclear Theory? An atom contains a region

  Options:
  A) which contains protons and neutrons
  B) which is positively charged
  C) which is massive and can cause deflection of a few projectiles
  D) which is very large and in which close to 98% of projectiles pass undeflected
  Show Answer
  The correct answer is C .
• Question 122:

  The knowledge of half-life can be used to

  Options:
  A) Create an element
  B) Detect an element
  C) Split an element
  D) Irradiate an element
  Show Answer
  The correct answer is C .
• Question 123:

  What is the main environmental concern associated with sulfur dioxide emissions?

  Options:
  A) Formation of acid rain
  B) Global warming potential
  C) Depletion of the stratospheric ozone
  D) Depletion of the ozone layer
  Show Answer
  The correct answer is A .
• Question 124: Which of the following does NOT contain aluminium as component? Options:
  A) Over-head cables
  B) Duralumin
  C) Container for caustic soda
  D) Container for nitric acid
  Show Answer
  The correct answer is D .
• Question 125:

  ZnO_(s) + CO_(g) → Zn_(s) + CO_2(g)

  In the reaction above, Zinc has been

  Options:
  A) decomposed
  B) displaced
  C) oxidized
  D) reduced
  Show Answer
  The correct answer is D .
• Question 126: The reaction of zinc with copper (ll) ions in aqueous solution can be represented as follows: Cu ²⁺(aq) +Zn (s) → Cu(s) + Zn ²⁺(aq).Which of the following is the most complete description of this reaction? Options:
  A) Cpper (ll) ions are being reduced
  B) Zinc is being oxidized.
  C) Copper (ll) ions and zinc are being reduced
  D) copper (ll) ions and zinc are being oxidized
  E) copper(ll) ions are being reduced and zinc oxidized
  Show Answer
  The correct answer is E .
• Question 127: The temperature of a body decreases when drops of liquid placed on it evaporate because? Options:
  A) the atmospheric vapour pressure has a cooling effect on the body
  B) a temperature gradient exists between the drops of liquid and the body causing the latter to vaporate
  C) the heat of vapourization is drawn from the body causing it to cool
  D) the random motion of the liquid molecules causes a cooling effect on the body
  Show Answer
  The correct answer is C .
• Question 128:

  In the reaction:

  M + N → P

  ΔH = +Q kJWhich of the following would increase the concentration of the product?

  Options:
  A) Adding a suitable catalyst
  B) Increasing the concentration of P
  C) Increasing the temperature
  D) Decreasing the temperature
  Show Answer
  The correct answer is C .
• Question 129: When a solution of silver (l) nitrate is saturated with hydrogen sulphide, a black precipitate forms which is? Options:
  A) H₂S
  B) Ag₂S
  C) PbS
  D) HNO₃
  E) S
  Show Answer
  The correct answer is B .
• Question 130: A compound that gives a brick-red colour to a non-luminous flame is likely to contain Options:
  A) copper ions
  B) sodium ions
  C) calcium ions
  D) aluminium ions
  Show Answer
  The correct answer is C .