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 971: The radioactive emission with the least ionization power is Options:
  A) $\alpha -particles$
  B) X-rays
  C) $\gamma -rays$
  D) $\beta -rays$
  Show Answer
  The correct answer is C .
• Question 972: Ethanol can easily be produced by Options:
  A) fermentation of starch
  B) distillation of starch solution
  C) catalytic oxidation of methane
  D) destructive distillation of wood
  Show Answer
  The correct answer is A .
• Question 973: According to Charle's law, the volume of a gas becomes zero at Options:
  A) −100°c
  B) −273°c
  C) −373°c
  D) 0°c
  Show Answer
  The correct answer is B .
• Question 974:

  

  In the experiment above, a current was passed for 10 minutes and 0.63g of copper was found to be deposited on the cathode of CuSO₄ cells. The weight of silver deposited on the cathode og AgNO³ cell during the same period would be? [Cu = 63, Ag = 108]

  Options:
  A) 0.54g
  B) 1.08g
  C) 1.62g
  D) 2.16g
  E) 3.24g
  Show Answer
  The correct answer is B .
• Question 975:

  Which of the following statements is true regarding the melting and boiling points of pure substances?

  Options:
  A) The boiling point is always higher than the melting point
  B) The melting point is always higher than the boiling point
  C) The melting and boiling points are always the same for all substances
  D) The melting and boiling points can vary depending on the substance
  Show Answer
  The correct answer is D .
• Question 976:

  CO_(g) + H₂O_(g) → CO_2(g) + H_2(g)

  From the reaction above, calculate the standard enthalpies of formation of CO_2(g), H₂O_(g) and CO_(g) in kJ mol^-1 are -394, -242, and -110 respectively.

  Options:
  A) -262 kJ mol^-1
  B) -42 kJ mol^-1
  C) +42 kJ mol^-1
  D) +262 kJ mol^-1
  Show Answer
  The correct answer is B .
• Question 977:

  220g of carbon dioxide contains ----- moles

  Options:
  A) 5
  B) 6
  C) 3
  D) 4
  Show Answer
  The correct answer is A .
• Question 978: When iron is exposed to moisture and it rusts, the value of ΔG for the reaction is Options:
  A) neutral
  B) zero
  C) positive
  D) negative
  Show Answer
  The correct answer is D .
• Question 979: Which of the following methods can be used to obtain pure water from a mixture of sand, water and methanoic acid? Options:
  A) netralization with NaOHfoolowed by filtration
  B) neutralization with NaOH followed by distillation
  C) fractional distillation
  D) filtration followed by distillation
  Show Answer
  The correct answer is D .
• Question 980:

  

  In the diagram, the function of the concentrated H₂SO₄ is to

  Options:
  A) purify the gas
  B) dry the gas
  C) liquefty the gas
  D) remove odour
  Show Answer
  The correct answer is B .