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 801: 10cm³ of hydrogen fluoride gas react with 5cm³ of dinitrogen difluoride gas (N²F₂) to form 10₃ of a single gas. Which of the following is the most likely equation of the reaction? Options:
  A) HF + N₂F₂ $\to$ N₂HF₃
  B) 2HF + N₂F₂ $\to$ 2NHF₂
  C) 2HF + N₂F₂ $\to$ N₂H₂F₃
  D) HF + 2N₂F₂ $\to$ N₄HF₂
  Show Answer
  The correct answer is B .
• Question 802: The mass of an atom is determined by Options:
  A) its ionization potential
  B) its electrochemical potential
  C) the number of protons and electrons
  D) the number of neutrons and protons
  E) the number of neutrons and electrons
  Show Answer
  The correct answer is D .
• Question 803: The arrangement of particles in crystal lattices can be studied using Options:
  A) X-rays
  B) $\beta$-rays
  C) $\alpha$-rays
  D) $\gamma$-rays
  Show Answer
  The correct answer is A .
• Question 804:

  The type of bonding in [Cu(NH${}_3$)${}^4$]${}^{2+}$ is 

  Options:
  A) coordinate
  B) electrovalent
  C) metallic
  D) covalent
  Show Answer
  The correct answer is A .
• Question 805:

  What unit of temperature should be used when applying the ideal gas law?

  Options:
  A) Fahrenheit (°F)
  B) Kelvin (K)
  C) Rankine (°R)
  D) Celsius (°C)
  Show Answer
  The correct answer is B .
• Question 806:

  What number of moles of Cu ²⁺ will be deposited by 360 coulombs of electricity?

  [f = 96500 C mol ^-1]

  Options:
  A) 5.36 x 10 ^-4 mole
  B) 1. 87 x 10 10 ^-3 mole
  C) 9. 35 x 10 ^-4 mole
  D) 3. 73 x 10 ^-3
  Show Answer
  The correct answer is B .
• Question 807:

  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 808: If 24.4 g of lead (ll) trioxonitrate (V) were dissolved in 42 g of distilled water at 20^oC; calculate the solubility of the solute in gdm^-3. Options:
  A) 581.000.
  B) 0.581
  C) 5.810
  D) 58.100
  Show Answer
  The correct answer is A .
• Question 809:

  What is the concentration of a solution containing 2g of NaOH in 100cm3 of solution? [Na = 23, O =16, H = 1]

  Options:
  A) 0.40 moldm${}^{-3}$
  B) 0.50 moldm${}^{-3}$
  C) 0.05 moldm${}^{-3}$
  D) 0.30 moldm${}^{-3}$
  Show Answer
  The correct answer is B .
• Question 810:

  The following are isoelectronic ions except

  Options:
  A) Na${}^{+}$
  B) Mg${}^{2+}$
  C) Si${}^{2+}$
  D) O${}^{2+}$
  Show Answer
  The correct answer is C .