Diisopropyl ether is a compound used as a solvent in paint thinners and stain removers. A 0.2150 g sample of diisopropyl ether was burned in excess oxygen which produced 0.5557 g CO₂(g) and 0.2654 g H₂O(l). A separate sample of diisopropyl ether vapor was placed in a 1.00 L vessel at 70.5°C and had a final pressure of 98.0 kPa. The mass of the vessel increased by 3.504 g.

If the enthalpy of combustion of diisopropyl ether is ΔH°_c = –4010.1 kJ/mol, calculate its standard enthalpy of formation (ΔH°_f).