Qualification > Sciences
Edexcel CHEMISTRY DOUBTS!!!!
Igcseboy:
--- Quote from: vanibharutham on May 16, 2010, 09:21:06 pm ---You prolly mean 24 d i) and ii)
d i) C9H20
ii) 3-ethyl-4-methylhexane
--- End quote ---
no the question in which we have to find enthalpy change using mean bond enthalpy....
Saladin:
--- Quote from: Igcseboy on May 17, 2010, 06:28:32 pm ---
no the question in which we have to find enthalpy change using mean bond enthalpy....
--- End quote ---
Saladin:
Sorry, that should be 490.
raimunts:
Speaking of enthalpy and stuff,
given there are 4 compunds A, B, C and D...and: A + B --> C + D
and standard enthalpy of formation/combustion is given for any three. Is it possible to find the remaining one from those three?
If it is, then what is the relationship?
vanibharutham:
One element must be O2 for it to be an enthalpy of combustion
in the attached file
1 = standard enthalpy of combustion of A
2 = standard enthalpy of formation of A
3 = standard enthalpy of formation of B
4 = standard enthalpy of formation of C
NB. O2 does an enthalpy of formation of 0 kJ/mol
using Hess's Law
1 = 3 + 4 - 2
just substitute in the values
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