Using the Supplemental Data, calculate the standard enthalpy change (in kJ/mol) for each of the following reactions. (a) Na(s) + O2(g) → NaO2(s) kJ/mol (b) 4 B(s) + 3O2(g) → 2 B₂O3(s) kJ/mol (c) Cr2O3(s) + 3 H2(g) → 2 Cr(s) + 3 H₂O(/) kJ/mol (d) 2 KOH(s) + CO2(g) → K2CO3(s) + H2O(g) kJ/mol