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 671:

  Which of the following statements about catalyst is false?

  Options:
  A) biological catalysts are called enzymes
  B) catalyst do not appear in the balanced equation
  C) catalyst reduce the activation energy for a reaction
  D) catalysts do not alter the mechanism of the reaction and never appear in the rate low
  Show Answer
  The correct answer is D .
• Question 672:

  The contact process is used for the industrial production of

  Options:
  A) sulfuric acid (H2SO4)
  B) Hydrochloric acid (HCl)
  C) Sodium hydroxide (NaOH)
  D) Calcium oxide (CaO)
  Show Answer
  The correct answer is A .
• Question 673: Stainless steel is used for making Options:
  A) magnets
  B) tools
  C) coins and medals
  D) moving parts of clocks
  Show Answer
  The correct answer is B .
• Question 674: Which of the following statements is true about 2-methylpropane and butane Options:
  A) They are members of the same homologous series
  B) They have the same boiling point
  C) They have different number of carbon atoms
  D) They have the same chemical properties
  Show Answer
  The correct answer is A .
• Question 675:

  2H${}_2$ + O${}_2$ 2H${}_2$O

  From the equationabove, calculate the volume of unreacted oxygen gas if a mixture of 50cm${}^3$ of hydroden and 75cm${}^3$ of oxygen are involved

  Options:
  A) 85cm${}^3$
  B) 50cm${}^3$
  C) 125cm${}^3$
  D) 55cm${}^3$
  Show Answer
  The correct answer is B .
• Question 676:

  Which of the following reactions would be expected to have the highest entropy change?

  Options:
  A) Liquid → Gas
  B) Solid → Liquid
  C) Gas → Liquid
  D) Gas → Solid
  Show Answer
  The correct answer is A .
• Question 677:

  What is Faraday's constant?

  Options:
  A) 6.022 x 10${}^{23}$ mol${}^{-1}$
  B) 3.00 x 10${}^8$ m/s
  C) 9.81 m/s${}^2$
  D) 96,485 C/mol
  Show Answer
  The correct answer is D .
• Question 678:

  200 cm³ of air was passed over heated copper in a syringe several times to produce copper (II) oxide.

  When cooled, the final volume of air recorded was 158cm³. Estimate the percentage of oxygen in the air?

  Options:
  A) 31%
  B) 27%
  C) 21%
  D) 19%
  Show Answer
  The correct answer is C .
• Question 679:

  The number of grammes of potassium hydroxide in 250cm³ of one molar solution is?

  (K = 39, O = 16, H = 1)

  Options:
  A) 40g
  B) 52g
  C) 100g
  D) 26g
  E) 14g
  Show Answer
  The correct answer is E .
• Question 680:

  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 .