Question in Chemistry ppr4 urgent plz.

[moon]

does anyone know why some books say
1) E(std)cell = E(+ve terminal) - E(-ve terminal)
2) E(std)cell = E(right hand terminal) - E(left hand terminal)

in my class, we used the first one. but when i attempt June 2008 paper4 Q1, they used the 2nd one to get the answer. im confused :S

thanks in advance.

 

[beacon_of_light]

Use this... E(of specie reduced) - E(of specie oxidised)

 

[moon]

thank u very much beacon

 

[mathmaster]

its the same thing. +ve terminal is the right hand terminal where ions gets reduced and are good oxidising agents
-ve terminal is the left hand terminal where substance are oxidised..thats why the less positive or negative E value are always from the left hand cell.