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 961:

  What current will deposit 3.25g of zinc in 2hrs?

  [Zn = 65, F = 96500 mol^-]

  Options:
  A) 3.25A
  B) 2.00A
  C) 1.34A
  D) 0.67A
  Show Answer
  The correct answer is C .
• Question 962:

  An unknown organic compound X has a relative molecular mass of 180. It is a colourless crystaline solid, readily soluble in water. X contains the elements C, H and O in the atomic ratio 1: 2:1. The compound has a sweet teste and melts on heating. In the presence of yeast and in the absence of air, X is converted to compound Y and a colourless gas. Compound Y reacts with sodium metal to produce a gas Z which gives a 'pop' sound with a glowing splint. Y also reacts with ethanoic acid to give a sweet smelling compound W.

  The molecular formula of X is

  Options:
  A) C₁₂H₂₂O₁₁
  B) C₆H₁₂O₆
  C) C₃H₆O ₃
  D) C₇H₁₄O₇
  E) C₁₂H₆O₄
  Show Answer
  The correct answer is B .
• Question 963: When air is compressed? Options:
  A) its density decreases
  B) it solidifies
  C) its temperature decreases
  D) its temperature increases
  E) its temperature remains unchanged
  Show Answer
  The correct answer is C .
• Question 964: Carbohydrates are large molecules with the molecular formula C _x (H₂O)_y. In which of the following pairs is x not equal to y? Options:
  A) glucose and starch
  B) maltose and starch
  C) sucrose and fructose
  D) maltose and starch
  Show Answer
  The correct answer is A .
• Question 965: Chlorine, bromine and iodine resemble one another in that they Options:
  A) dissolve in alkalis
  B) react violently with hydorgen without heating
  C) are liquids
  D) displace one another from solutiions of their salts
  Show Answer
  The correct answer is D .
• Question 966: 2- methylbutan- 2ol is an example of a Options:
  A) dihydric alkanol
  B) tertiary alkanol
  C) secondary alkanol
  D) primary alkanol
  Show Answer
  The correct answer is B .
• Question 967:

  Which of the following is a common property of non-metals?

  Options:
  A) Exist as solids at room temperature
  B) Tend to gain electrons in chemical reactions
  C) High thermal conductivity
  D) Readily form cations in chemical reactions
  Show Answer
  The correct answer is B .
• Question 968: Which of the following compounds reacts with sodium metal as well as silver and copper salts ? Options:
  A) CH₃C Ξ C—CH₃
  B) CH₃CH₂CH₂₃>
  C) CH₃C Ξ CH
  D) CH₃CH = CH CH₃
  Show Answer
  The correct answer is C .
• Question 969: If 30cm³ of gas at 50^oC is warmed to 80^o at a fixed pressure, the fractional increase in volume is Options:
  A) 0.009
  B) 0.093
  C) 0.910
  D) 1.090
  Show Answer
  The correct answer is B .
• Question 970: In which of the following reactions has the oxidation number of nitrogen increased? Options:
  A) 2NO_(g) + Br_2(l) → 2NOBr_(l)
  B) 2NO_(g) + O_2(g) → 2NO_2(g)
  C) FeSO_4(aq) + NO_(g) → Fe(NO)SO_4(s)
  D) 2NO(g) + Cl_2(g) → 2NOCl(l)
  Show Answer
  The correct answer is B .