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 1351:

  What happens when alkanoic acids react with alcohols in the presence of an acid catalyst?

  Options:
  A) Saponification
  B) Esterification
  C) Polymerization
  D) Hydrolysis
  Show Answer
  The correct answer is B .
• Question 1352: For a general equation of the nature xP + yQ → mR + nS, the expression for the equilibrium constant is Options:
  A) k [P]^x [Q]^y
  B) $\frac{[P{]}^x[Q{]}^y}{[R{]}^m[S{]}^n}$
  C) $\frac{[R{]}^m[S{]}^n}{[P{]}^x[Q{]}^y}$
  D) $\frac{m[R]n[S]}{x[P]y[Q]}$
  Show Answer
  The correct answer is C .
• Question 1353:

  At 2.0 atm pressure, the volume of a gas is 4.0 L. If the pressure is reduced to 1.0 atm while keeping the temperature constant, what will be the new volume of the gas?

  Options:
  A) 2.0 L
  B) 6.0 L
  C) 8.0 L
  D) 4.0 L
  Show Answer
  The correct answer is C .
• Question 1354:

  

  The following graph demonstrates the rate of reaction between calcium carbonate (marble)and dilute hydrochloric acid. The graph shows that the rate of reaction is initially greatest when

  Options:
  A) the initial slope of the curve is steepest and this occur when small pieces of marble are used and is due to a small surface area of reactant
  B) the occur when large pieces of marble are used and is due to a small surface area of reactant
  C) the initial slope of the curve is steepest and this occurs when small pieces of marble are used and is due to a large surface area of reactant
  D) the initial slope of the curve is steepest and this occur when large surface area of reactant
  E) the initial slope of the curve is least steep and this occur when small pieces of marble are used and is due to the increased surface area of the reactant
  Show Answer
  The correct answer is C .
• Question 1355: Which of the following equimolar solutions will have the highest pH? Options:
  A) CH₃COOHa
  B) NaOH
  C) HCl
  D) NH₄OH
  Show Answer
  The correct answer is B .
• Question 1356:

  A compound contains 31.91% potassium, 28.93% chlorine and the rest oxygen. What is the chemical formula of the compound?

  [K = 39, Cl = 35.5, O = 16]

  Options:
  A) KClO₄
  B) KClO
  C) KClO₂
  D) KClO₃
  Show Answer
  The correct answer is D .
• Question 1357:

  2SO_2(g) + O_2(g) $⟺$2SO_3(g)

  $△H=-395.7kJmo{l}^{-1}$

  In the reaction above, the concentration of 2SO_3(g) can be in creased by

  Options:
  A) decreasing the pressure
  B) decreasing the temperature
  C) the addition of catalyst
  D) increasing the temperature
  Show Answer
  The correct answer is B .
• Question 1358: Cathode rays causes an object placed behind a perforated anode to cast a shadow on the screen. This observation shows that the rays Options:
  A) are positively charged
  B) are negatively charged
  C) have mass
  D) travel in straight lines
  Show Answer
  The correct answer is D .
• Question 1359: How many grams of HBr would exactly be required to react with 2 g of propyne? (C =12, H=1, Br = 80) Options:
  A) 4. 1 g
  B) 6. 1 g
  C) 8. 1g
  D) 16.2g
  Show Answer
  The correct answer is C .
• Question 1360:

  Calculate the percentage composition of oxygen in calcium trioxocarbonate(IV) [Ca=40, C=12, O=16]

  Options:
  A) 16
  B) 48
  C) 40
  D) 12
  Show Answer
  The correct answer is B .