Chemistry 2018 Past Questions | WAEC

Study the following Chemistry past questions and answers for JAMBWAEC  NECO and Post-JAMB. Get prepared with official past questions and answers for upcoming examinations.

41.  What is the relative molecular mass of a compound which has empirical formula \(CH_{2}O\)?   [C= 12, H= 1, O= 16]

    • A. 42
    • B. 45
    • C. 126
    • D. 180

42.  Atoms are electrically neutral because they

  • A. do not conduct electricity
  • B. contain equal number of protons and electrons
  • C. are composed of neutrons and electrons
  • D. cannot be attracted by electromagnetic field.

43. Common Salt (NaCl) is used to preserve foods. Which of the following properties can be used to determine its purity before use?

  • A. Solubility in water
  • B. Melting point
  • C. Relative density
  • D. Crystalline nature

44.  Which of the following electron configurations represents the transition element Chromium \(_{24}Cr\)?

  • A. \(1s^{2} 2s^{2} 2p^{6} 3s^{2} 3p^{6} 4s^{2} 3d^{4}\)
  • B. \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{6}\)
  • C. \(1s^{2}2s^{2}2p^{6}3s^{2}3d^{4} 4s^{1}\)
  • D. \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{1}3d^{5}\)

45. The atomic number of an isotope of hydrogen is equal to its mass number because it

  • A. has a totally filled valence shell
  • B. has a high charge to mass ratio
  • C. does not contain neutrons
  • D. exhibits isotopy
 

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The atomic number of an isotope of hydrogen is equal to its mass number because it

  • A. has a totally filled valence shell
  • B. has a high charge to mass ratio
  • C. does not contain neutrons
  • D. exhibits isotopy

47. The bonding pair of electrons in a Hydrogen Chloride molecule is pulled towards the chlorine atom because 

  • A. chlorine has a larger atomic size
  • B. chlorine has a larger atomic mass
  • C. chlorine is more electronegative
  • D. there is no bonding orbitals within the hydrogen atom

48. The solubility of CO2 in water can be accounted for by

  • A. Van der Waal’s forces
  • B. Ionic attraction
  • C. dipole attraction
  • D. covalent bonding

49. Which of the following properties would not influence electrovalent bond formation?

  • A. Electronegativity
  • B. Electron Affinity
  • C. Ionization potential
  • D. Catalytic ability
 

50. Particles in a solid exibit

  • A. vibrational motion
  • B. vibrational and translational motion
  • C. vibrational and random motion
  • D. random and translational motion

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