8. Thermochemistry

Calculate the standard enthalpy change (ΔH°_rxn) for the reaction: 2 Br₂(l) + C₂H₂(g) → C₂H₂Br₄(l) using the given bond energies.

Given the thermochemical equation 3 C(s) + 4 H₂(g) → C₃H₈(g), what is the standard enthalpy change of formation (ΔHf°) for propane, C₃H₈(g)?

A 100.0 mL sample of 0.300 M NaOH is mixed with a 100.0 mL sample of 0.300 M HCl in a coffee cup calorimeter. If both solutions were initially at 35.00°C and the temperature of the resulting solution was recorded as 37.00°C, determine the ΔH°rxn (in kJ/mol) for the neutralization reaction.

A 100 mL sample of 0.3 M NaOH is mixed with a 100 mL sample of 0.3 M HCl in a coffee cup calorimeter. If both solutions were initially at 35°C and the temperature of the resulting solution was recorded as 37°C, determine ΔH_rxn (in units of kJ/mol NaOH) for the reaction.

A 6.61 g sample of an unknown salt (MM = 116.82 g/mol) is dissolved in 150.00 g of water in a coffee cup calorimeter. Before placing the sample in the water, the temperature of the salt and water is 23.72 °C. After the salt has completely dissolved, the temperature of the solution is measured to be 20.15 °C. What is the enthalpy change (ΔH) for the dissolution of the salt in kJ/mol?

What is the enthalpy change (ΔH) for the dissolution of 2.50 g of substance X in water, given that the temperature of the solution increases from 12.0 °C to 27.0 °C?

A sample of steam with a mass of 0.521 g at a temperature of 100 °C condenses into an insulated container holding 4.45 g of water at 2.0 °C. For water, ΔHvap = 40.7 kJ/mol and Cwater = 4.18 J/(g·°C). Assuming that no heat is lost, what is the final temperature of the water in the container?

An 8.5 g ice cube is placed into 255 g of water. Calculate the temperature change in the water upon the complete melting of the ice. Assume that all of the energy required to melt the ice comes from the water. The enthalpy of fusion (ΔH_fusion) is 6.02 kJ/mol. What is the temperature change in the water?

What is the standard enthalpy change for the combustion of one mole of benzene (C6H6) based on the given thermochemical equation: 2 C6H6(l) + 15 O2(g) → 12 CO2(g) + 6 H2O(l) ΔHrxn° = -6534 kJ?

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?