# 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

46.

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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