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more cie chem doubts

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Sue T:
(ppr 2)in nov 04 ques 3 (a)iii
at the anode th oxidation number goes from -1 to 0 (oxidation)
at the cathode the oxidation num is supposed 2 go from +1 to 0 (reduction)
th ms says -1 to 0 at th cathode- is t a mistake?

one more question  ;D
nov05 Q2 (d)
shouldnt it be like : -395+(2*-298)+(delta H formation) = -1110      ???
its exothermic since bonds r formed so the answer must be negative
but in th ms its positive (they did it in a diff way)

Lana Wolf:
the papers arent opening... :S
some prob in freeexampapers..??

nid404:
nov 04....that's a mistake..

nov 05
 
You need to calculate enthalpy change of formation of CS2

so C+2S`--->CS2

S+O2--->SO2 -298kj/mol   X2
C+O2--->CO2   -395kj/mol
CS2+3O2---> CO2+2SO2 -1110kj/mol

-395+ (-298X2)+dh--->1110 (become postive because it is on the other(product)side of the main reaction)
dh=1110-(991)
=+119kj/mol

Sue T:
OOooo! got it
thx alot again!  ;)

sweetie:
Hey,
am also confused about Q4 parts "c" and"d" of paper2 nov04

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