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 171: An example of a solid emulsion is Options:
  A) Butter
  B) Hair cream
  C) Milk
  D) Cod-liver oil
  Show Answer
  The correct answer is A .
• Question 172:

  

  Use the table above to answer this question. The element that is likely to participate in covalent rather than ionic bonding is

  Options:
  A) Z
  B) Y
  C) X
  D) W
  Show Answer
  The correct answer is C .
• Question 173:

  Which of the following conditions will most enhance the spontaneity of a reaction?

  Options:
  A) $\mathrm{\Delta }$H is negative and greater than T$\mathrm{\Delta }$S
  B) $\mathrm{\Delta }$H is negative and $\mathrm{\Delta }$S = 0
  C) $\mathrm{\Delta }$H is positive and less than T$\mathrm{\Delta }$S
  D) $\mathrm{\Delta }$H is positive and equal to T$\mathrm{\Delta }$S
  Show Answer
  The correct answer is A .
• Question 174:

  Which of the following statements is correct about the periodic table?

  Options:
  A) Elements in the same period have the same number of valence electrons
  B) The valence electrons of the elements in the same period increase progressively across the period
  C) Elements in the same group have the same number of electron shells
  D) The non-metallic Properties of the elements tend to decrease across each period
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  The correct answer is B .
• Question 175: A pair of compounds that can be used to generate a gas which has physiological effect on human beings is Options:
  A) sodium trioxonitrate (V) and calcium chloride
  B) sodium dioxonitrate (III) and ammonium chloride
  C) sodium trioxonitrate (V) and ammonium chloride
  D) sodium dioxonitrate (III) and potassium chloride
  Show Answer
  The correct answer is A .
• Question 176:

  An organic compound that does not undergo a reaction with both hydrogen cyanide and hydroxylamine can be?

  Options:
  A) Alkene
  B) Alkanal
  C) Alkanone
  D) Alkanoic Acid
  Show Answer
  The correct answer is A .
• Question 177:

  

  Use the graph above to answer this question.

  A sample, X, solid at room temperature, was melted, heated to a temperature of 358 K and allowed to cool as shown in OPQR. The section PQ indicates that X is

  Options:
  A) a mixture of salts
  B) a hydrated salt
  C) an ionic salt
  D) a pure compound
  Show Answer
  The correct answer is D .
• Question 178: An endothermic reaction is one during which heat is.....and can be represented by the symbol.... which of the following combinations can be used accurately to complete the above definition? Options:
  A) liberated, -$\mathrm{\Delta }$H
  B) liberated, +$\mathrm{\Delta }$H
  C) absorbed, -$\mathrm{\Delta }$H
  D) absorbed, +$\mathrm{\Delta }$H
  E) absorbed, +$\mathrm{\Delta }$G
  Show Answer
  The correct answer is D .
• Question 179: Which of the following classes of organic compounds undergoes rapid oxidation with bromine water? Options:
  A) alcohols
  B) alkenes
  C) carboxylic acids
  D) esters
  E) alkanes
  Show Answer
  The correct answer is B .
• Question 180: The solubility of a salt of molar mass 101g at 20^oC is 0.34 mol dm^-3. If 3.40g of the salt is dissolved completely in 250cm³ of water in a beaker, the resulting solution is Options:
  A) A suspension
  B) Saturated
  C) Unsaturated
  D) Supersaturated
  Show Answer
  The correct answer is C .