solution..???

[umarashraf]

how we find enthalphy changes..?? bye subtracting Reactants energy from products energy or how..???

 

[MysteRyGiRl]

haii
if we have 2 find the combustion enthalpy from formation then its reactants minus products
opposite 4 formation
n v have multiply it if number of atoms r given
i fnk m rite

 

[umarashraf]

you just fink or sure..???

 

[MysteRyGiRl]

lol w8 4 smbdy else 2 answer 4 100% cnfrmation

 

[umarashraf]

hmmm.. this is the best which can be done..

 

[Lifeless]

how we find enthalphy changes..?? bye subtracting Reactants energy from products energy or how..???

When heat of formation is given, then enthalpy change of the reaction will be = product - (reactant).

But when no heat of formation is given, we can calculate by adding up all the bond energies of the reaction. However remember to take the values of bond energies that bond breaking is positive and bond breaking must be negative. So in short u can write : (sum of bond breaking energies) - (sum of bond forming energies)
(as bond breaking is endothermic and bond forming is exothermic)