Demonstrations of Magnetism and Oxidation by Combustion of Iron Supplement Tablets

• Max J. Palmer ^[1] ; Keri A. Martinez ^[1] ; Mayuresh G. Gadgil ^[1] ; Dean J. Campbell ^[1]
  1. [1] Bradley University

     Bradley University

     Township of Peoria City, Estados Unidos

     
• Localización: Journal of chemical education, ISSN 0021-9584, Vol. 95, Nº 3, 2018, págs. 423-427
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • Iron supplement tablets containing iron(II) sulfate can be used in chemistry demonstrations as a convenient, household source of small quantities of iron(II) ions. When the tablet is burned in air, oxygen converts the iron(II) in the tablet ultimately to iron(III) oxide in the hematite phase. Heating pure iron(II) sulfate heptahydrate also produces hematite. However, for the tablet, and for mixtures of iron(II) sulfate heptahydrate and starch, other iron oxide species such as magnetite and maghemite are produced before complete conversion to hematite. The presence of the starch, and cellulose in the tablets, appears to slow the oxidation of the iron(II). Magnetite and maghemite can be captured, observed by X-ray diffraction, and are much more strongly attracted to a magnet than hematite. The changes in color and magnetic susceptibility during iron supplement tablet combustion enable it to be used as an interesting demonstration of oxidation.