Question

estimate the enthalpy change for each of the following reaction:
a) H2C=O(g)+HCl(g .....> H3C-O-Cl(g)
b)H2O2(g)+2CO(g).....> H2(g)+2CO2(g)
c)3H2C=CH2(g).....> C6H12(g)
(the six carbon atoms form a six-membered ring with two H atoms on each C atom)

Answer 1

All of these are gases; I would use bond energies.
dHrxn = (n*BE reactants) - (n*BE products)
You should have a table in your book with bond energies.

Answer 2

the answer to b is -416

Answer 3

345