The ΔH°_f of TiI₃(s) is –328 kJ/mol and the ΔH ° for the reaction 2 Ti(s) + 3 I₂(g) → 2 TiI₃(s) is –839 kJ. Calculate the ΔH of sublimation of I₂(s), which is a solid at 25 °C.

A gaseous fuel mixture contains 25.3% methane (CH₄), 38.2% ethane (C₂H₆), and the rest propane (C₃H₈) by volume. When the fuel mixture contained in a 1.55 L tank, stored at 755 mmHg and 298 K, undergoes complete combustion, how much heat is emitted? (Assume that the water produced by the combustion is in the gaseous state.)

The ΔH for the oxidation of sulfur in the gas phase to SO₃ is –204 kJ/mol and for the oxidation of SO₂ to SO₃ is 89.5 kJ/mol. Find the enthalpy of formation of SO₂ under these conditions.

A gaseous fuel mixture stored at 745 mmHg and 298 K contains only methane (CH₄) and propane (C₃H₈). When 11.7 L of this fuel mixture is burned, it produces 769 kJ of heat. What is the mole fraction of methane in the mixture? (Assume that the water produced by the combustion is in the gaseous state.)

When 10.00 g of phosphorus is burned in O₂(g) to form P₄O₁₀(s), enough heat is generated to raise the temperature of 2950 g of water from 18.0 °C to 38.0 °C. Calculate the enthalpy of formation of P₄O₁₀(s) under these conditions.

A 20.0-L volume of an ideal gas in a cylinder with a piston is at a pressure of 3.0 atm. Enough weight is suddenly removed from the piston to lower the external pressure to 1.5 atm. The gas then expands at constant temperature until its pressure is 1.5 atm. Find w.