Chemistry 2018 Past Questions | JAMB

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.

21. In the preparation of oxygen by heating KCIO, in the presence of MnO2 only moderate heat is needed because the catalyst acts by

  • A.  Lowering the pressure of the reaction
  • B. Increasing the surface area of the reaction
  • C. Increasing the rate of the reaction
  • D. Lowering the energy barrier of the reaction

22.  Methanoic acid mixes with water in all proportions and has about the same boiling point as water. Which of the following methods would you adopt to obtain pure water from a mixture of Sand, water and methanoic acid?

  • A. Fractional distillation
  • B. Filtration followed by distillation
  • C. Neutralization with sodium hydroxide followed by distillation
  • D. Neutralization with sodium hydroxide followed by filtration

23. A quantity of electricity liberates 3.6g of Silver from its salt. What mass of aluminium Will be liberated from its salt by the same quantity of electricity? [Al = 27, Ag = 108].

  • A. 2.7g
  • B. 1.2g
  • C. 0.9g
  • D. 0.3g

24. Suitable reagents for the laboratory preparation nitrogen are

  • A. Sodium dioxonitrate(III) and ammonium chloride
  • B. Sodium trioxonitrate(V) and ammonium chloride
  • C. Sodium chloride and ammonium trioxonitrate(V)
  • D. Sodium chloride and ammonium di-ozonitrate(III)

15.The number of electrons in the valence shell of an element of atomic number 14 is?

  • A. 1
  • B. 2
  • C.3
  • D. 4

26. What volume of oxygen will remain after reacting 8cm of hydrogen gas with 20cm of oxygen gas

  • A. 10cm3
  • B. 12cm3
  • C. 14cm3
  • D. 16cm3

27.  If one of the following oxides is heated with hydrogen or carbon using a bunsen burner. it is not reduced to the metal, Which one is it?

  • A. Lead oxide
  • B. Magnesium oxide
  • C. Copper oxide
  • D. Tin oxide

28.

CUNv388sqQ8UA6ZJdnDoWhgDT6qJFZVk36kU8hUd

IUPAC name for

  • A. 1-methyl pentane
  • B. 3-methylbutane
  • C. 2-methylbutane
  • D. 1-dimethyl propane

29.  An aqueous solution of a metal salt, M. gives a white precipitate with NaOH which dissolves in excess NaOH. With aqueous ammonia, the solution of M also gives a white precipitate which dissolves in excess ammonia Therefore the cation in M is

  • A.Zn
  • B. Ca
  • C. Al
  • D. Po

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

  • A.  0.40 moldm
  • B. 0.50 moldm
  • C. 0.05 moldm
  • D. 0.30 moldm

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