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 161: Tartaric acid is used industrially to Options:
  A) make baking powder
  B) make fruit juices
  C) remove rust
  D) dry substance
  Show Answer
  The correct answer is A .
• Question 162:

  The heat of reaction can be determined experimentally using a device called a

  Options:
  A) Calorimeter
  B) Barometer
  C) Spectrometer
  D) Thermometer
  Show Answer
  The correct answer is A .
• Question 163:

  

  Use the figure above to answer this question. Which of the following compounds is an isomer of the compound

  Options:
  A) A
  B) B
  C) C
  D) D
  Show Answer
  The correct answer is D .
• Question 164:

  Who proposed the planetary model of the atom with electrons orbiting the nucleus?

  Options:
  A) Erwin Schrödinger
  B) Ernest Rutherford
  C) Niels Bohr
  D) J.J. Thomson
  Show Answer
  The correct answer is C .
• Question 165: In the redox reaction 2Fe²⁺ + CI₂ → 2Fe ^{3 +} + 2Cl Options:
  A) Cl₂ is reduced because it has lost electrons
  B) Cl₂ is reduced because its oxidation number has decreased
  C) Cl₂ is reduced because its molecule is change to two ions
  D) Fe²⁺ is reduced because it has lost electrons
  E) Fe²⁺ is reduced because it has gained electrons
  Show Answer
  The correct answer is B .
• Question 166:

  Balance the following redox reaction:
  Fe${}_2$O${}_3$+ CO Fe + CO${}_2$

  Options:
  A) Fe${}_2$O${}_3$ + CO → 2Fe + 2CO${}_2$
  B) 2Fe${}_2$O${}_3$ + 3CO → 4Fe + 3CO${}_2$
  C) Fe${}_2$O${}_3$ + 2CO → 2Fe + 2CO${}_2$
  D) Fe${}_2$O${}_3$ + 3CO → 2Fe + 3CO${}_2$
  Show Answer
  The correct answer is D .
• Question 167: How many lone pairs of electron are there on the central atom of the H₂O molecules? Options:
  A) 1
  B) 2
  C) 3
  D) 4
  Show Answer
  The correct answer is B .
• Question 168:

  CH_4(g) + CI_2(g) $\to$ CH₂CI_(s) + HCI_g

  The major factor that influences the rate of the reaction above is

  Options:
  A) Concentration
  B) Catalyst
  C) Temperature
  D) Light
  Show Answer
  The correct answer is D .
• Question 169: Carbohydrates are large molecules with the molecular formula C _x (H₂O)_y. In which of the following pairs is x not equal to y? Options:
  A) glucose and starch
  B) maltose and starch
  C) sucrose and fructose
  D) maltose and starch
  Show Answer
  The correct answer is A .
• Question 170:

  Cr₂O₇^2-_(aq) + 14H⁺_(aq) + 6l^-_(aq) → 2Cr³⁺_(aq) + 3l_(g) + 7H₂O_(I).

  The change in the oxidation number of oxygen in the equation above is?

  Options:
  A) 1
  B) 2
  C) 7
  D) 0
  Show Answer
  The correct answer is D .