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 991: A phenomenon where an element exist in different forms in the same physical state is known as Options:
  A) isomerism
  B) amorphism
  C) allotropy
  D) isotopy
  Show Answer
  The correct answer is C .
• Question 992:

  

  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 993: 25 cm³ of 0.02 M KOH neutralized 0.03 g of a monobasic organic acid having the general formula C_nH_{2n + 1} COOH. The molecular formula of the acid is?(C = 12, H = 1, O = 16) Options:
  A) HCOOH
  B) C₂H₅COOH
  C) CH₃COOH
  D) C₃H₇COOH
  Show Answer
  The correct answer is C .
• Question 994: Terylene is synthesized from ethane- 1, 2-diol and benzene - 1, 4-dicarboxylic acid by? Options:
  A) addition reaction
  B) condensation reaction
  C) elimination reaction
  D) substitution reaction
  Show Answer
  The correct answer is B .
• Question 995: NH_3(g) + HCl_(s) → NH ₄Cl _(s)The entropy change in the system above is Options:
  A) positive
  B) zero
  C) negative
  D) intermediate
  Show Answer
  The correct answer is C .
• Question 996:

  Which of the following alkaline metals react more quickly spontaneously with water?

  Options:
  A) Calcium
  B) Beryllium
  C) Magnesium
  D) Strontium
  Show Answer
  The correct answer is A .
• Question 997: Which of the following CANNOT be obtained by fractional distillation of petroleum? Options:
  A) Ether
  B) Methane
  C) Butane
  D) Ethene
  E) Hydrogen
  Show Answer
  The correct answer is E .
• Question 998:

  An element, X, forms a volatile hydride XH₃ with a vapour density of 17.0. The relative atomic mass of X is?

  (H = 1)

  Options:
  A) 34.0
  B) 31.0
  C) 20.0
  D) 14.0
  Show Answer
  The correct answer is B .
• Question 999: The volume of a given gas is V cm³P mm Hg. what is the new volume of the gas if the pressure is reduced to half at constant temperature Options:
  A) 4 V cm³
  B) 2 V cm³
  C) V/2 cm³
  D) V cm³
  Show Answer
  The correct answer is B .
• Question 1000: According to the kinetic theory an absence in temperature causes the kinetic energy of particles to Options:
  A) decrease
  B) increase
  C) remain constant
  D) be zero
  Show Answer
  The correct answer is D .