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Electrochemical reactions involve the transfer ofelectrons. Mass and charge are conserved whenbalancing these reactions, but you need to knowwhich atoms are oxidized and which atoms arereduced during the reaction. Oxidationnumbersare used to keep track of how manyelectrons are lost or gained by each atom. Theseoxidation numbers are assigned using thefollowing rules:

. The convention is that the cation iswritten frst in a ormula, ollowed by theanion.!or example, in "a#, the # is #$% in #&l, the # is#'.

(. The oxidation number o a ree

element is always 0.The atoms in #e and "(, for example, haveoxidation numbers of ).

*. The oxidation number o a monatomic

ion equals the charge o the ion.!or example, the oxidation number of "a'is '%the oxidation number of "*$is $*.

+. The usual oxidation number ohydrogen is +1.

The oxidation number of hydrogen is $ incompounds containing elements that arelesselectronegativethan hydrogen, as in &a#(.

#ow To ssign -xidation "umbers

The oxidation number o oxygen incomounds is usually !".Exceptions include -!(, since ! is moreelectronegative than -, and a-(, due to thestructure of the peroxide ion, which is /-$-0($.

. The oxidation number o a #rou $%elementin a comound is +1.

(. The oxidation number o a #rou $$%elementin a comound is +".

*. The oxidation number o a #rou &$$%elementin a comound is !1, excet whenthat element is combined with one having ahigher electronegativity.

The oxidation number of &l is $ in #&l, but theoxidation number of &l is ' in #-&l.

+. The sum o the oxidation numbers oall o the atoms in a neutral comound is 0.

1. The sum o the oxidation numbers ina olyatomic ion is equal to the charge othe ion.!or example, the sum of the oxidation numbersfor 2-+

($is $(.

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'(OT analysis3alternatively '(OT matrix4 is an acronymfor strengths,weaknesses, opportunities,and threats5and is a structured planningmethod that evaluates those four elements ofa pro6ector businessventure. 27-T analysis can be carried out for a company, product, place, industry,or person. 8t involves specifying the ob6ective of the business venture or pro6ect and identifying the internaand external factors that are favorable and unfavorable to achieve that ob6ective. 2ome authors credit27-T to lbert #umphrey,who led a convention at the 2tanford 9esearch 8nstitute 3now 298 8nternational4in the ;)s and erent ob6ective and repeat the process.?sers of 27-T analysis must ask and answer @uestions that generate meaningful information for eachcategory 3strengths, weaknesses, opportunities, and threats4 to make the analysis useful and =nd theircompetitive advantage.

)Aa customer perceived preference for and evaluation of those products attributes, attributeperformances, and conse@uences arising from use that facilitate 3or block4 achieving the customerBsgoals and purposes in use situationsC.

The de=nition above suggests that there are two aspects to customer value: desired value andperceived value. Desired value refers to what customers desire in a product or service. erceived valueis the bene=t that a customer believes he or she received from a product after it was purchased.

&ustomer value can be examined at di>erent levels. t a low level, customer value can be viewed as

the attributes of a product that a customer perceives to receive value from. t a higher level, customervalue can be viewed as the emotional payo> and achievement of a goal or desire. 7hen customersderive value from a product, they derive value from the attributes of the product as well as from theattribute performance and the conse@uence of achieving desired goals from the use of the product.

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