so listen
while doing these enthalpy reactions
u wil be given the kj/mol for the formation of two bonds like for example if u want to find the enthalpy for the formation of HCl
it would be like this
H-H =678 kj
Cl-Cl = 343 kj
and H-Cl = 478kj
then u add H-H and Cl-Cl
and subtract from H-Cl
over here it will be (478-(678+343))
which will result in a -ve value
hence when the value is negative it is an exothermic reaction
dont worry lol
u will be given the table for the energies
so yeah thats basically it!
