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 851:

  

  In the diagram above , the activation energy for the backward reaction is

  Options:
  A) +5kJ
  B) +15KJ
  C) +25KJ
  D) +30KJ
  Show Answer
  The correct answer is C .
• Question 852:

  The nucleusof a hydrogen atom consist of a?

  Options:
  A) 1 proton only
  B) 1 proton, 2 neutron
  C) 1 neutron only
  D) 1 electron only
  Show Answer
  The correct answer is A .
• Question 853: CH₃COOC₂H₅(1) + H₂O₍₁₎ ⇌ CH ₃COOH _(aq) + C ₂H ₅OH _(aq)The purpose of H⁺ in the reaction above is to Options:
  A) increase the yield of products
  B) maintain the solution at a constant PH
  C) increase the rate of the hydrolysis
  D) decrease the rate of the reverse reaction
  Show Answer
  The correct answer is A .
• Question 854: The atomic radius of Li, Na and K are 1: 33A, 1. 54A and 1. 96A res pectively. Which of the following explaqins this gradation in atomic radius? Options:
  A) electropositivity decreases from Li to Na to K
  B) electronegativity decreases from Li to Na to K
  C) the number of the electron shells increases from Li to Na to K
  D) the elements are in the same period
  Show Answer
  The correct answer is C .
• Question 855: The saponification of an alkanoate to produce soap and alkanol involves Options:
  A) dehydration
  B) esterification
  C) hydrolysis
  D) oxidation
  Show Answer
  The correct answer is C .
• Question 856: Detergents have the general formula? Options:
  A) R(CH₂)_nOH
  B) RSO₃^-Na⁺
  C) RSO^-₂Na⁺
  D) RSO₂H
  Show Answer
  The correct answer is B .
• Question 857: The Arrhenius equation expresses the relationship between the speed of a reaction and its Options:
  A) Molecular collision
  B) Heat of reaction
  C) Catalyst
  D) Activation energy
  Show Answer
  The correct answer is A .
• Question 858: The reaction of carbide with water gives Options:
  A) ethyne
  B) ethene
  C) ethane
  D) ethanal
  Show Answer
  The correct answer is A .
• Question 859: A hydrocarbon has an empirical formula CH and a vapour density of 39. Determine its molecular formula.[C = 12, H = 1] Options:
  A) C₂H₆
  B) C₃H₈
  C) C₃H₄
  D) C₆H₆
  Show Answer
  The correct answer is D .
• Question 860:

  CH₃-CH-CH₃

  CH₂CI Is known as?

  Options:
  A) 1-chloro-2-methylbutane
  B) 1-chloro-2-methylpropane
  C) 2-chloromethylpropane
  D) 1-chloro-2, 2-dimethylethane
  Show Answer
  The correct answer is B .