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 1531: An element with atomic number twelve is likely to be Options:
  A) electrovalent with a velocity of 1
  B) electrovalent with a valency of 2
  C) covalent with a valency of 2
  D) covalent with valency of 4
  Show Answer
  The correct answer is B .
• Question 1532: Moving from left to right across a period, the general rise in the first ionization energy can be attributed to the Options:
  A) decrease in nuclear charge
  B) increase in nuclear charge
  C) decrease in screening effect
  D) increase in screening effect
  Show Answer
  The correct answer is B .
• Question 1533: The removal of rust from iron by treatment with tetraoxosulphate (IV) acid is based on the? Options:
  A) hydrolysis of the iron
  B) reaction of acid with base
  C) oxidationof the rust
  D) dehydration of the iron
  Show Answer
  The correct answer is D .
• Question 1534: What volume of 1.5M solution of KOH would contain 0.045 moles Options:
  A) 67.50 cm³
  B) 30.00 cm³
  C) 6.75 cm³
  D) 3.00 cm³
  Show Answer
  The correct answer is B .
• Question 1535: Rare gases are suitable because they Options:
  A) are monoatomic
  B) form ions easily
  C) have duplet or octet electronic configuration in the outermost shells in their atoms
  D) are volatile gases
  Show Answer
  The correct answer is C .
• Question 1536: The stability of the noble gases is due to the fact that they Options:
  A) have no electron in their outermost shells
  B) have duplet or octet electron configurations
  C) belong to group zero of the periodic table
  D) are volatile in nature
  Show Answer
  The correct answer is B .
• Question 1537: Oxygen gas can be prepared by heating? Options:
  A) ammonium trioxonitrate (V)
  B) ammonium trioxonitrate (III)
  C) ppotassium trioxonitrate (V)
  D) mamgamese (IV) oxide
  Show Answer
  The correct answer is C .
• Question 1538: In the chemical reaction A + B $\to$ C + D, more of D is formed? Options:
  A) if the concentrated of A is reduced
  B) if the concentrated of B is reduced
  C) if the concentrated of C is reduced
  D) if the concentration of C is increased
  E) if D is continuously removed from the reaction mixture
  Show Answer
  The correct answer is E .
• Question 1539: Geometric isomerism can exist in Options:
  A) hex-3-ene
  B) hexane
  C) prop-l-ene
  D) 3-methyl but -l-ene
  Show Answer
  The correct answer is A .
• Question 1540: Air boiled out of water as steam is richer in Options:
  A) nitrogen and oxygen
  B) carbon (IV) oxide and oxygen
  C) noble gases and carbon (IV) oxide
  D) oxygen and noble gases
  Show Answer
  The correct answer is B .