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 841: If 30cm³ of gas at 50^oC is warmed to 80^o at a fixed pressure, the fractional increase in volume is Options:
  A) 0.009
  B) 0.093
  C) 0.910
  D) 1.090
  Show Answer
  The correct answer is B .
• Question 842:

  The electronic configuration of an element is 1S${}^2$ 2S${}^2$ 2P${}^6$ 3S${}^2$ 3P${}^3$. How many unpaired electrons are there in the element?

  Options:
  A) 5
  B) 4
  C) 3
  D) 2
  Show Answer
  The correct answer is C .
• Question 843:

  MnO_2(s) + xHCl_(aq) → MnCl_2(aq) + yH₂O_(l) + zCl_2(g)

  In theequation above, what are the values of x, y and z respectively

  Options:
  A) 2, 1, 2
  B) 4, 1, 2
  C) 4, 2, 1
  D) 1, 2, 1
  Show Answer
  The correct answer is C .
• Question 844: If the silver mirror test is positive, it indicates the presence of an Options:
  A) alkyne
  B) alkanol
  C) alkanone
  D) alkanal
  Show Answer
  The correct answer is D .
• Question 845:

  Elements P, Q, R, S have 6, 11, 15, 17 electrons respectively, therefore,

  Options:
  A) P will form an electrovalent bond with R
  B) Q will form a covalent bond with S
  C) R will form an electrovalent bond with S
  D) Q will form an electrovalent bond with S
  Show Answer
  The correct answer is D .
• Question 846: A reaction takes places spontaneously if?
  Options:
  A) ∆G = O
  B) ∆S < O and ∆H > O
  C) ∆H < T ∆S
  D) ∆G > O
  Show Answer
  The correct answer is C .
• Question 847: Which of the following metals will displace iron from a solution of iron(ll)tetraoxosulphate(lV)? Options:
  A) Copper
  B) Mercury
  C) Silver
  D) Zinc
  E) Gold
  Show Answer
  The correct answer is D .
• Question 848: How many structural isomers can be written for the alkyl bromide, C₄H₉Br? Options:
  A) 3
  B) 4
  C) 6
  D) 8
  Show Answer
  The correct answer is B .
• Question 849:

  

  The acidic hydrogen in the compound is the hydrogen attached to carbon number

  Options:
  A) 5
  B) 4
  C) 3
  D) 1
  Show Answer
  The correct answer is D .
• Question 850: Four elements P,Q, R and S have atomic numbers of 4, 10, 12 and 14 respectively . Which of these electrons is a noble gas? Options:
  A) P
  B) Q
  C) R
  D) S
  Show Answer
  The correct answer is B .