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 1361:

  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 1362: Which of the following statements is true? When the potassium atom forms its ion Options:
  A) it gains one electron and becomes neutral
  B) its atomic number decreases
  C) it achieves electronic configuration of orgon
  D) it loses one proton
  E) it loses one neutron
  Show Answer
  The correct answer is C .
• Question 1363:

  CH₃COOH_(aq) + OH^-_(aq) ↔ CH₃COO^-_(aq) + H₂O_(l)

  In the reaction above ,CH₃COO^-_(aq) is

  Options:
  A) conjugate base
  B) acid
  C) base
  D) conjugate acid
  Show Answer
  The correct answer is A .
• Question 1364:

  

  In the above experiment X is

  Options:
  A) pure nitrogen
  B) a mixture of nitrogen and oxygen
  C) a mixture of nitrogen and carbondioxide
  D) a mixture of oxygen and inert gases
  E) a mixture of nitrogen and inert gases
  Show Answer
  The correct answer is E .
• Question 1365: The compound produced when sodium peroxide is heated with excess sodium is Options:
  A) Na₂CO₃
  B) Na₂O
  C) NaNO₂
  D) NaOH
  Show Answer
  The correct answer is B .
• Question 1366:

  How many neutrons are present in atom with mass number and atomic number 37 and 17 respectively?

  Options:
  A) 18
  B) 20
  C) 37
  D) 17
  Show Answer
  The correct answer is B .
• Question 1367: The characteristic colour of the flame shown when a copper sail moistened with concentrated hydrochloric acid on a platinum wire is put on bunsen burner is Options:
  A) lilac
  B) green
  C) yellow
  D) brick-red
  Show Answer
  The correct answer is B .
• Question 1368:

  PCl_5(g) ↔ PCl_3(g) + Cl_2(g)

  In the reaction above, a decrease in pressure will

  Options:
  A) Decelerate the reaction
  B) Increase the yield of PCl₃
  C) Increase the yield of PCl₅
  D) Accelerate the reaction
  Show Answer
  The correct answer is B .
• Question 1369: The property used in obtaining oxygen and nitrogen industrially from air is the? Options:
  A) boiling point
  B) density
  C) rate of diffusion
  D) solubility
  Show Answer
  The correct answer is A .
• Question 1370: Cotton is almost pure? Options:
  A) starch
  B) protein
  C) animal fibre
  D) celluose
  E) mineral fibre
  Show Answer
  The correct answer is D .