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 611: The synthetic detergents are preferred to soap for laundry using hard water because? Options:
  A) detergents are water soluble while soap is not
  B) the calcium salts of detergents are water soluble
  C) the magnesium salt of soap is soluble in hard water
  D) soap does not have a hydrocarbon terminal chain
  Show Answer
  The correct answer is B .
• Question 612: How many protons, neutrons and electrons respectively are present in the element 60/27 Co? Options:
  A) 27, 33 and 33
  B) 33, 27 and 27
  C) 27, 33, and 27
  D) 60, 33 and 60
  Show Answer
  The correct answer is C .
• Question 613:

  Which group does calcium belong to in the periodic table?

  Options:
  A) Alkaline earth metals
  B) Halogens
  C) Alkali metals
  D) Noble gases
  Show Answer
  The correct answer is A .
• Question 614:

  A gaseous metallic chloride MCl consists of 20.22% of M by mass. The formula of the chloride is?

  [ M = 27, Cl = 35.5]

  Options:
  A) MCl
  B) MCl${}_2$
  C) MCl${}_3$
  D) M${}_2$Cl${}_6$
  Show Answer
  The correct answer is C .
• Question 615: A red precipitate of copper (I) carbide is formed when ammonium solution of copper (I) chloride is introduced into Options:
  A) CH₂ = CH - CH₂ - CH₃
  B) CH₃ CH₂ - C ≡ CH
  C) CH₃ CH₂ CH₂ CH₃
  D) CH₃ - C C - CH₃
  Show Answer
  The correct answer is B .
• Question 616: 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 617: For a given solute, the concentration of its saturated solution in different solvents are Options:
  A) the same at the same temperature
  B) different at the same temperature
  C) the same at different temperature
  D) constant
  Show Answer
  The correct answer is B .
• Question 618: 90.0g of MgCI₂ was placed in 50.0cm³ of water to give a saturated solubility of the salt is 8.0 mol dm³ at the same temperature, what is the mass of the salt left undissolved at the given temperature?(Mg = 24, Cl = 35.5) Options:
  A) 52.0g
  B) 58.5g
  C) 85.5g
  D) 88.5g
  Show Answer
  The correct answer is A .
• Question 619:

  

  The diagram above represents an atom that can combine with chlorine to form

  Options:
  A) a covalent bond
  B) an electrovalent bond
  C) a hydrogen bond
  D) a co-ordinate bond
  Show Answer
  The correct answer is B .
• Question 620:

  Balance the following redox reaction:
  Fe${}_2$O${}_3$+ CO Fe + CO${}_2$

  Options:
  A) Fe${}_2$O${}_3$ + CO → 2Fe + 2CO${}_2$
  B) 2Fe${}_2$O${}_3$ + 3CO → 4Fe + 3CO${}_2$
  C) Fe${}_2$O${}_3$ + 2CO → 2Fe + 2CO${}_2$
  D) Fe${}_2$O${}_3$ + 3CO → 2Fe + 3CO${}_2$
  Show Answer
  The correct answer is D .