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 1801: A piece of metal (M) is dissolved in nitric acid and the resulting solution is treated with a small quantity of sodium hydroxide to produce a white precipitate (B) which redissolves on the addition of excess alkali. The precipitate (B)when ignited in a crucible produces the oxide of the metal(m). The METAL M is Options:
  A) Zn
  B) Cu
  C) Al
  D) Au
  E) Ca
  Show Answer
  The correct answer is A .
• Question 1802:

  Which of the following reactions is (are) feasible?

  I Br ₍₁₎ + 2CI _2(aq) 2Br _(aq) + CI _2(g)

  Ll 21 _(aq) + Br ₂₍₁₎ 2Br _(aq) + 1 _2(s)

  Lll 2F _(aq) + CI _2(g) 2CI _(aq) + F _2(g) IV 2F _(aq) + Br ₂₍₁₎ 2Br _(aq) + F _2(g)

  Options:
  A) l
  B) ll
  C) l and lll
  D) lll and lV
  Show Answer
  The correct answer is B .
• Question 1803: 25cm³ of a gas X contains Z molecules at 15^oC and 75 mmHg. How many molecules will 25 cm³ of another gas Y contain at the same temperature and pressure? Options:
  A) 2 Y
  B) 2 Z
  C) Z
  D) Y
  Show Answer
  The correct answer is C .
• Question 1804: Oxygen is a mixture of two isotopes O and O with relative abundances of 90% and 10% respectively. The relative atomic mass of oxygen is? Options:
  A) 16.0
  B) 16.2
  C) 17.0
  D) 18.0
  Show Answer
  The correct answer is B .
• Question 1805: The densities of two gases, X and Y are 0.5gdm^-3 and 2.0gdm^-3 respectively. What is the rate of diffusion of X relative to Y? Options:
  A) 0.1
  B) 0.5
  C) 2.0
  D) 4.0
  Show Answer
  The correct answer is C .
• Question 1806: Atomicity of ozone is Options:
  A) 1
  B) 2
  C) 3
  D) 4
  Show Answer
  The correct answer is C .
• Question 1807:

  A given amount of gas occupies 10.0dm5 at 4atm and 273°C. The number of moles of the gas present is [Molar volume of gas at s.t.p = 22.4dm${}^3$]

  Options:
  A) 0.89 mol
  B) 1.90 mol
  C) 3.80 mol
  D) 5.70 mol
  Show Answer
  The correct answer is A .
• Question 1808: The exhaust fumes from a garage in a place that uses petrol of high sulphur content are bound to contain? Options:
  A) CO and SO₃
  B) CO and SO₂
  C) CO,SO₂ and SO₃
  D) CO and H₂S
  Show Answer
  The correct answer is B .
• Question 1809:

  One of the following is not a physical property of monosaccharides?

  Options:
  A) Monosaccharides get charred when heated
  B) Monosaccharides are water-soluble, sweet substances
  C) They are highly vital to the exploration of metals
  D) They can be reduced to sugar alcohols
  Show Answer
  The correct answer is C .
• Question 1810:

  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 .