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 751:

  Hydrogen bond is a sort of

  Options:
  A) van der waals force
  B) dative bond
  C) ionic bond
  D) a covalent bond
  Show Answer
  The correct answer is D .
• Question 752: A blue solid, T, which weighed 5.0g was placed on a table. After 8 hours, the resulting pink solid was found to weigh 5.5g. It can be inferred that substance T? Options:
  A) is deliquescent
  B) is hydroscopic
  C) has some molecules of water of crystallization
  D) is efflorescent
  Show Answer
  The correct answer is A .
• Question 753: For iron to rust, there should be present? Options:
  A) oxygen
  B) moisture
  C) carbondioxide
  D) oxygen and moisture
  E) oxygen, moisture and carbondioxide
  Show Answer
  The correct answer is D .
• Question 754:

  Soaps clean surfaces on the principlebased on?

  Options:
  A) viscosity
  B) floatation
  C) elasticity
  D) surface tension
  Show Answer
  The correct answer is D .
• Question 755: A side effect of soft water is that Options:
  A) it gives offensive taste
  B) excess calcium is precipitated
  C) it attcaks lead contained in pipes
  D) it encourages the growth of bacteria
  Show Answer
  The correct answer is C .
• Question 756: Suitable reagents for the laboratory preparation nitrogen are? Options:
  A) sodium dioxonitrate (III) and ammonium chloride
  B) sodium dioxonitrate (V) and ammonium chloride
  C) sodium chloride and ammonium chloride
  D) sodium chloride and ammonium diozonitrate (III)
  Show Answer
  The correct answer is A .
• Question 757: Which of the following sets of metals dissolves in dilute HCl? Options:
  A) Fe, Sn and Cu
  B) Mg, Fe and Cu
  C) Mg, Sn and Fe
  D) Cu, Mg and Sn
  Show Answer
  The correct answer is C .
• Question 758: A mixture contains 20cm³ of hydrogen, 35cm³ of oxygen, 15cm³ of carbon monoxide and 10cm³ of nitrogen at S.T.P. Which of the following gives the mole fraction of hydrogen in this mixture? Options:
  A) 0.02
  B) 0.16
  C) 0.20
  D) 0.25
  E) 20
  Show Answer
  The correct answer is D .
• Question 759: Calculate the volume of 0.5 mol dm^-3 H₂So₄ that is neutralized by 25 cm³ of 0.1 mol dm^-3 NaOH Options:
  A) 5.0 cm³
  B) 2.5 cm³
  C) 0.4 cm³
  D) 0.1 cm³
  Show Answer
  The correct answer is B .
• Question 760: In the preparation of some pure crystals of Cu (NO₃)₂ starting with CuO, a student gave the following statements as steps he employed. Which of these shows a flaw in his report ? Options:
  A) some CuO was reacted with excess dilute H₂SO₄
  B) the solution was concentrated
  C) when the concentrate was cooled, crystals formed were removed by filtration
  D) the crystals were washed with very little cold water
  E) the crystals were then allowed to dry
  Show Answer
  The correct answer is A .