Choose the thermochemical equation that illustrates ΔH°f for K2SO4(s).

Calculate ΔG°rxn at 25°C for the reaction: 2CH4(g) → C2H6(g) + H2(g). Given the following standard Gibbs free energies of formation: ΔG°f(CH4) = -50.8 kJ/mol, ΔG°f(C2H6) = -32.8 kJ/mol, ΔG°f(H2) = 0 kJ/mol.

Calculate the enthalpy change (ΔH°) for the following reaction at 25 °C using the given standard enthalpies of formation (ΔfH°) in kJ/mol: 2H2(g) + O2(g) → 2H2O(l). Given: ΔfH°[H2(g)] = 0, ΔfH°[O2(g)] = 0, ΔfH°[H2O(l)] = -285.8.

Calculate the value of ΔH° in kJ for the following reaction: 4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(l), given the following standard enthalpies of formation: ΔHf°[NH3(g)] = -45.9 kJ/mol, ΔHf°[NO(g)] = 90.3 kJ/mol, ΔHf°[H2O(l)] = -285.8 kJ/mol.

Calculate ΔrH for the reaction: CH4(g) + 4 Cl2(g) → CCl4(g) + 4 HCl(g) using the given ΔfH values: CH4(g) ΔfH = -74.6 kJ/mol, CCl4(g) ΔfH = -95.7 kJ/mol, and HCl(g) ΔfH = -92.3 kJ/mol.

Consider the following generic reaction: A + 2 B → 3 C + D; ΔH = 623 kJ. What would be the value of ΔH for the following reaction: 1/3 A + 2/3 B → C + 1/3 D?

Given the thermochemical equation CH4(g) + 2O2(g) → CO2(g) + 2H2O(g) with ΔH°rxn = -802.3 kJ, what minimum mass of CH4 is required to heat 85.0 g of water by 30.0 °C, assuming 100% heating efficiency? (For water, Cs = 4.18 J/g°C).

How much heat is absorbed when 30.00 g of C(s) reacts in the presence of excess SO2(g) to produce CS2(l) and CO(g) according to the following chemical equation? 5 C(s) + 2 SO2(g) → CS2(l) + 4 CO(g), ΔH = 239.9 kJ

Mothballs are composed primarily of the hydrocarbon naphthalene (C10H8). When 0.820 g of naphthalene burns in a bomb calorimeter, the temperature rises from 25.10 °C to 31.56 °C. Find ΔErxn for the combustion of naphthalene given that the heat capacity of the calorimeter is 5.50 kJ/°C.