Chapter 5 - analysing oxidants and reductants

CHAPTER 5 - ANALYSING OXIDANTS AND REDUCTANTS oxidation involves a loss of electrons reduction involves a gain of electrons oxidation and reduction reactions occur simultaneously an oxidant causes oxidation and is itself reduced a reductant causes reduction and is itself oxidised oxidation numbers can be used to identify species that have been oxidised or reduced oxidation numbers have no physical meaning an element has been oxidised if its oxidation number has increased an element has been reduced if its oxidation number has decreased an oxidation or a reduction reaction can be represented by a half equation an oxidation half equation and a reduction half equation can be combined by multiplying the half equations so that there is an equal number of electrons in each half equation. The half equations can hen be added. volumetric analysis can be used to determine the concentration or mass of substances that undergo redox reactions

BALANCING HALF EQUATIONS1. write the formula of the species being oxidised/reduced and its conjugate pair2.balance the number of atoms of the species being oxidised/reduced3.balance the number of oxygen atoms by adding H2O to the equation4.balance the number of hydrogen atoms by adding H+ to the equation (H+ comes from the acidified solution)5.balance the charges by adding electrons6.add states for all species

increase in oxidation number=oxidised=reductantdecrease in oxidation number=reduced=oxidant

OIL RIG

REDOX REACTION: a reaction that involves the transfer of electrons from chemical to another.

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