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 1921:

  

  Use the graph above to answer this question.

  A sample, X, solid at room temperature, was melted, heated to a temperature of 358 K and allowed to cool as shown in OPQR. The section PQ indicates that X is

  Options:
  A) a mixture of salts
  B) a hydrated salt
  C) an ionic salt
  D) a pure compound
  Show Answer
  The correct answer is D .
• Question 1922: Copper sulphate solution is electolysed using platinum electrodes A. current of 0.193 amperes is passed for 2hrs. How many grams of copper are deposited? (cu = 63.5, F = 96500 coulombs) Options:
  A) 0.457g
  B) 0.500g
  C) 0.882g
  D) 0.914g
  E) 1.00g
  Show Answer
  The correct answer is A .
• Question 1923: 50cm of carbon (II) oxide exploded with 150cm${}^3$ of air containing 20% oxygen by volume. Which of the reactants was in excess? Options:
  A) carbon (II) oxide
  B) carbon (IV) oxide
  C) oxygen
  D) nitrogen
  Show Answer
  The correct answer is C .
• Question 1924:

  In the laboratory preparation of oxygen, the gas cannot be collected by displacement of air because

  Options:
  A) the density of oxygen is greater than that of air
  B) the density of air is nearly the same as that of oxygen
  C) oxygen is a component of air
  D) air is an impure substance
  Show Answer
  The correct answer is A .
• Question 1925: How many moles of (H+) are there in 1 dm³ of 0.5 M solution of H₂SO₄? Options:
  A) 2.0 moles
  B) 1.0 moles
  C) 0.5 mole
  D) 0.25 mole
  Show Answer
  The correct answer is B .
• Question 1926:

  The dehydration of CH${}_3$CH${}_2$CH${}_2$CH${}_2$OH will give?

  Options:
  A) HC≡CCH${}_2$CH${}_3$
  B) CH${}_2$≡CH${}_2$CH${}_3$
  C) CH${}_3$C≡CCH${}_3$
  D) CH${}_3$CH=CHCH${}_3$
  Show Answer
  The correct answer is D .
• Question 1927:

  The general formula of alkanones is

  Options:
  A) RCHO
  B) R${}_2$CO
  C) RCOOH
  D) RCOOR
  Show Answer
  The correct answer is B .
• Question 1928: The IUPAC nomenclature of the compound LiAlH₄ is Options:
  A) lithiumtetrahydridoaluminate (III)
  B) aluminium tetrahydrido lithium
  C) tetrahydrido lithium aluminate (III)
  D) lithium aluminium hydride
  Show Answer
  The correct answer is A .
• Question 1929: The gas that is most useful in protecting humans against solar marathon is Options:
  A) chlorine
  B) ozone
  C) carbon IV oxide
  D) hydrogen sulphur
  Show Answer
  The correct answer is B .
• Question 1930:

  The size (diameter) of five elements are in the order R < T < W < X < Y, Y being the largest. If each atom has an electron situated on its circumference, and neglecting other factors, which of the atoms will lose its electron most reluctantly?

  Options:
  A) R
  B) T
  C) W
  D) X
  E) Y
  Show Answer
  The correct answer is A .