Oxidation Number Oxidizer

Oxidation Number Oxidation Level One-Carbon Form Tetrahydrofolate Form... 

Oxidation increases the oxidation number of an element reduction decreases the oxidation number. Oxidation numbers are assigned by using the rules in Toolbox K.l. 

Oxidation-reduction (redox) reactions involve the loss of electrons and increase in oxidation number (oxidation) by one substance or system, with an associated gain of electrons and decrease in oxidation number (reduction) by another substance or system. Thus for every oxidation reaction there must be a reduction reaction. The oxidation number of an atom represents the hypothetical charge an atom would have if the ion or molecule were to dissociate.46-47... 

Unfortunately, many compounds contain bonds that are a mixture of ionic and covalent. In such a case, a formal charge as written is unlikely to represent the actual number of charges gained or lost. For example, the complex ferrocyanide anion [Fe(CN)6]4- is prepared from aqueous Fe2+, but the central iron atom in the complex definitely does not bear a +2 charge (in fact, the charge is likely to be nearer +1.5). Therefore, we employ the concept of oxidation number. Oxidation numbers are cited with Roman numbers, so the oxidation number of the iron atom in the ferrocyanide complex is +11. The IUPAC name for the complex requires the oxidation number we call it hexacyanoferrate (II). 

Define oxidation, reduction, oxidation number, oxidizing agent, and reducing agent. 

Oxidation number Oxidation state. A measure of the degree of oxidation of an atom in a substance. Oxidation The loss of electrons. 

Oxidation-reduction reactions Oxidation number Oxidizing and reducing agents Ionic notation for equations Balancing oxidation-reduction equations... 

Element Oxidation Number as Reactant Oxidation Number as Product Change in Oxidation Number Oxidation or Reduction... 

As you know, when an atom loses electrons, its oxidation number increases when an atom gains electrons, its oxidation number decreases. Therefore, the total increase in oxidation numbers (oxidation) must equal the total decrease in oxidation numbers (reduction) of the atoms involved in the reaction. The balancing technique called the oxidation-number method is based on these principles. The CHEMLAB at the end of this chapter gives you the opportunity to perform and balance the copper-nitric acid redox reaction. 

Identifying oxidation-reduction reactions and their components Reduction is the gain of an electron by a molecule, atom, or ion, thus decreasing its oxidation number. Oxidation is the loss of an electron, thus increasing the oxidation number of the molecule, atom, or ion. These two processes always occur together in oxidation-reduction reactions, also called redox reactions. Electrons lost by one substance are gained by the other. 

The reaction (4.145) describes all chemical reactions in which atoms have their oxidation number (oxidation state) changed. Oxidation state is defined as the charge an atom might be imagined to have when electrons are counted according to the following agreed set of rules (Table 4.6) ... 

Is a species that has an atom for which there is an increase in oxidation number oxidized or reduced Is that species the oxidizing agent or the reducing agent ... 

SECTION 4.4 Oxidation is the loss of electrons by a substance, whereas reduction is the gain of electrons by a substance. Oxidation numbers keep track of electrons during chemical reactions and are assigned to atoms using specific rules. The oxidation of an element results in an increase in its oxidation number, whereas reduction is accompanied by a decrease in oxidation number. Oxidation is always accompanied by reduction, giving oxidation-reduction, or redox, reactions. 

We determine whether a given chemical reaction is an oxidation-reduction reaction by keeping track of the oxidation numbers oxidation states) of the elements involved in the reaction. — (Section 4.4) This procedure identifies whether the oxidation state changes for any elements involved in the reaction. For example, consider the reaction that occurs spontaneously when zinc metal is added to a strong acid (T FIGURE 20.1) ... 

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