b. The decomposition reaction may be written in this form:

C12O36H20N12 (s) → 12CO2 (g) + O2 (g) + 6N2 (g) + 10H2O (l)
In the enthalpy diagram below, the arrows represent standard enthalpy reactions. (3) denotes the standard enthalpy of decomposition of C12O36H20N12 (s). Provide an appropriate label for the arrows (1), (2) and (4).

(3) C12O36H20N12 (s) --> 12CO2 (g) + O2 (g) + 6N2 (g) + 10H2O(l)
(1) 12C (s) + 18O2 (g) + 6N2 (g) + 10H2 (g) --> 12CO2 (g) + 6O2 (g) + 6N2 (g) + 10H2 (g)
(2) 12CO2 (g) + 6O2 (g) + 6N2 (g) + 10H2 (g) --> 12CO2 (g) + O2 (g) + 6N2 (g) + 10H2O(l)
(4) 12C (s) + 18O2 (g) + 6N2 (g) + 10H2 (g) --> C12O36H20N12 (s)

To provide appropriate labels for the arrows (1), (2), and (4), let's analyze the reactions:

(1) 12C (s) + 18O2 (g) + 6N2 (g) + 10H2 (g) → 12CO2 (g) + 6O2 (g) + 6N2 (g) + 10H2 (g)

This reaction appears to involve the combustion of carbon, nitrogen, and hydrogen. Therefore, an appropriate label for arrow (1) could be "Combustion of C, N, and H".

(2) 12CO2 (g) + 6O2 (g) + 6N2 (g) + 10H2 (g) → 12CO2 (g) + O2 (g) + 6N2 (g) + 10H2O (l)

This reaction seems to involve the conversion of some of the reactants (CO2, O2, N2, and H2) into products (CO2, O2, N2, and H2O). However, there is a decrease in the number of moles of water (l) compared to the number of moles of reactants. Therefore, an appropriate label for arrow (2) could be "Reaction with Water Condensation".

(4) 12C (s) + 18O2 (g) + 6N2 (g) + 10H2 (g) → C12O36H20N12 (s)

This reaction appears to involve the formation of the solid compound C12O36H20N12 from its constituent elements. Therefore, an appropriate label for arrow (4) could be "Formation of C12O36H20N12".

By analyzing the reactions and considering the changes occurring in each reaction, we can label the arrows accordingly.