8. Thermochemistry

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.

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

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.

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 5.90 kJ/°C.

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. If the heat capacity of the calorimeter is 5.11 kJ/°C, what is the ΔErxn for the combustion of naphthalene?

Sodium metal reacts with water to produce hydrogen gas and sodium hydroxide according to the chemical equation shown below. When 0.025 mol of Na is added to 100.00 g of water, the temperature of the resulting solution rises from 25.00°C to 35.75°C. If the specific heat capacity of water is 4.18 J/g°C, what is the enthalpy change (ΔH) for the reaction per mole of Na?

What is the approximate enthalpy change for the combustion of ethane in the reaction: 2 CH3-CH3(g) + 7 O2(g) → 4 CO2(g) + 6 H2O(g)?

The combustion of ethanol is shown below. C2H5OH(l) + 3O2(g) → 2CO2(g) + 3H2O(g) ΔH = –1367 kJ mol–1. The enthalpy change for the combustion of 12.5 g of ethanol is:

Which of the following reactions correctly represents the heat of hydration for the dissolution of gaseous sodium ions (Na+) in water?