13.2 g of iron(III) alum were dissolved in water and reduced to an iron(II) ion solution zinc and dilute sulfuric acid. The mixture was filtered and the filtrate and washings we
made
up
to 500 cm in a standard volumetric flask. If 20.0 cm of this solution
required 26.5 cm of 0.0100 mol dm- KMnO4 for oxidation:
a) give the ionic equation for the reduction of iron(III) ions by zinc metal.
(b) Calculate the percentage by mass of iron in iron alum.​

chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. these processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. understanding chemical changes is a major part of the science of chemistry.