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 1441:

  

  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 1442: Insoluble salts can be prepared by Options:
  A) titrating an alkali against an appropriate acid
  B) reacting an acid with trioxocarbonatr (IV) salt
  C) directing combination of the elements which make up the salt
  D) mixing two soluble compounds containing the metallic radical and the acidic radical
  Show Answer
  The correct answer is D .
• Question 1443: Synthetic rubber is made by polymerization of? Options:
  A) 2 methyl buta - 1, 3 - diene
  B) 2 methyl buta - 1, 2 - diene
  C) 2 methyl but -1-ene
  D) 2 methyl but-2-ene
  Show Answer
  The correct answer is A .
• Question 1444: In what way is equilibrium constant for the forward reaction related to that of the reversed reaction? Options:
  A) The additional of the two is expected to be one
  B) The product of the two is expected to be one
  C) The two equilibrium constants are identical
  D) The product of the two is always greater than one
  Show Answer
  The correct answer is A .
• Question 1445: As the difference in electronegativity between bonded atoms increases, polarity of the bond? Options:
  A) decreases
  B) increases
  C) remains unchanged
  D) reduces to zero
  Show Answer
  The correct answer is B .
• Question 1446: If the silver mirror test is positive, it indicates the presence of an Options:
  A) alkyne
  B) alkanol
  C) alkanone
  D) alkanal
  Show Answer
  The correct answer is D .
• Question 1447: When dilute hydrochloric acid is added to iron(ll)sulphide, the gas evolved will? Options:
  A) turn moist red litmus paper blue
  B) turn lime water milky
  C) blacken lead acurate paper
  D) rekindle a glowing splint
  E) burn a sqeakly pop
  Show Answer
  The correct answer is C .
• Question 1448: H^- + H_2(I)O → H_2(g) + OH^-_(aq). From the equation above, it can be inferred that the? Options:
  A) reaction is a double decomposition
  B) hydride ion is a reducing agent
  C) hydride ion is an oxidizing agent
  D) reaction is neutralization
  Show Answer
  The correct answer is B .
• Question 1449: The residual solids from the fractional distillation of petroleum are used as Options:
  A) coatings of pipes
  B) raw materials for the cracking process
  C) fuel for the driving tractors
  D) fuel for jet engines
  Show Answer
  The correct answer is A .
• Question 1450: Nitrogen obtained from the liquefaction of air has a higher density than that obtained from nitrogen containing compounds because the former contains Options:
  A) water vapour
  B) oxygen
  C) carbon (IV) oxide
  D) rare gases
  Show Answer
  The correct answer is D .