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 1081:

  Electrons enter into orbitals in order of increasing energy as exemplified by?

  Options:
  A) 1S${}^2$2S${}^2$2PX${}^2$2py${}^2$2pz${}^0$3s${}^0$
  B) 1S${}^2$2S${}^2$2PX${}^2$2py${}^1$2pz${}^1$3s${}^0$
  C) 1S${}^2$2S${}^2$2PX${}^1$2py${}^1$2pz${}^1$3s${}^1$
  D) 1S${}^2$2S${}^2$2PX${}^2$2py${}^2$2pz${}^0$3s${}^1$
  Show Answer
  The correct answer is B .
• Question 1082:

  By what amount must the temperature of 200cm${}^3$ of Nitrogen at 27°C be increased to double the pressure if the final volume is 150cm${}^3$ (Assume ideality)

  Options:
  A) 150°C
  B) 177°C
  C) 75°C
  D) 120°C
  Show Answer
  The correct answer is B .
• Question 1083:

  How many bonding pair are present in carbon(iv)oxide?

  Options:
  A) 4
  B) 3
  C) 2
  D) 1
  Show Answer
  The correct answer is A .
• Question 1084: A mixture of sugar and sulphur can be separated by Options:
  A) dissolution in water, evapouration and filtration
  B) filtration, evaporation and dissolution in water
  C) dissolution in water, filtration and evaporation
  D) evaporation, dissolution in water and filtration
  Show Answer
  The correct answer is C .
• Question 1085: Trioxonitrate (V) acid is not used for preparing hydrogen gas from metals because it Options:
  A) is strongly oxidizing
  B) is volatile
  C) renders the metal passive
  D) forms a layer of oxide on the metal
  Show Answer
  The correct answer is A .
• Question 1086: Atomicity of ozone is Options:
  A) 1
  B) 2
  C) 3
  D) 4
  Show Answer
  The correct answer is C .
• Question 1087:

  Which of the following statements is correct about the periodic table?

  Options:
  A) Elements in the same period have the same number of valence electrons
  B) The valence electrons of the elements in the same period increase progressively across the period
  C) Elements in the same group have the same number of electron shells
  D) The non-metallic Properties of the elements tend to decrease across each period
  Show Answer
  The correct answer is B .
• Question 1088: ${}_{88}^{226}Ra$ → ${}_{86}^{x}Rn$ + alpha particle Options:
  A) 226
  B) 220
  C) 227
  D) 222
  Show Answer
  The correct answer is D .
• Question 1089:

  The only metal that is anti-bacterial is?

  Options:
  A) Iron
  B) Sodium
  C) Alluminium
  D) Copper
  Show Answer
  The correct answer is D .
• Question 1090:

  How many bonding pair are present in carbon(iv)oxide?

  Options:
  A) 4
  B) 3
  C) 2
  D) 1
  Show Answer
  The correct answer is A .