8. Thermochemistry

What is the enthalpy change (ΔH) for the dissolution of 1 mole of substance X in water, given that the temperature of the solution increases from 12.0 °C to 30.0 °C when 1.40 g of X is dissolved in 35.0 mL of water? Assume the specific heat capacity of water is 4.18 J/g°C and the density of water is 1.00 g/mL.

Which of the following expressions correctly calculates the change in enthalpy (ΔH) for a reaction using standard heats of formation?

Which of the following statements is true regarding the enthalpy change of a reaction when the quantities of reactants are doubled?

Calculate the enthalpy change for the reaction: NO(g) + O(g) -> NO2(g), given the following standard enthalpies of formation: ΔHf°[NO(g)] = 90.25 kJ/mol, ΔHf°[O(g)] = 249.17 kJ/mol, ΔHf°[NO2(g)] = 33.18 kJ/mol.

Calculate the standard enthalpy change for the following reaction at 25°C using the standard enthalpies of formation: C3H8 (g) + 5O2 (g) -> 3CO2 (g) + 4H2O (g). Given: ΔHf° [C3H8 (g)] = -104.7 kJ/mol, ΔHf° [CO2 (g)] = -393.5 kJ/mol, ΔHf° [H2O (g)] = -241.8 kJ/mol.

Choose the reaction that illustrates the standard enthalpy of formation (ΔHf°) for Ca(NO2)2.

Which of the following reactions represents the standard enthalpy of formation (ΔHₒƒ) for CsHSO4(s)?

Consider the combination reaction: 2Mg(s) + O2(g) → 2MgO(s) with ΔH = -1204 kJ. What is the enthalpy change for the decomposition of 1 mole of MgO(s) into Mg(s) and O2(g)?

Which of the following statements correctly describes the calculation of the enthalpy change (ΔH_rxn) for a chemical reaction using bond enthalpies?

What is the standard enthalpy of formation of the isomer C8H18 if the enthalpy change for its complete combustion is -5470 kJ/mol?

For which of the following reactions is the enthalpy change for the reaction equal to the standard enthalpy of formation (ΔHf°) of the product?

The enthalpy change for the following reaction is -483.6 kJ: 2 H2 (g) + O2 (g) --> 2 H2O (g). Therefore, the enthalpy change for the following reaction is ________ kJ: 6 H2O (g) --> 6 H2 (g) + 3 O2 (g).

Given the reaction Pb (s) + CO2 (g) → PbO (s) + CO (g) with ΔH° = +131.4 kJ, and the standard enthalpies of formation ΔHf° of CO2(g) = -393.5 kJ/mol and CO(g) = -110.5 kJ/mol, what is the standard enthalpy of formation for PbO(s)?

The enthalpy for the formation of 1 mole of NH₃(aq) is -80.29 kJ/mol. What is the enthalpy for the formation of 3 moles of NH₃(aq)?

Given the heat of formation of TiI3(s) is -328 kJ/mol and the heat of reaction for 2Ti(s) + 3I2(g) → 2TiI3(s) is -839 kJ, what is the heat of sublimation of I2(s) at 25°C?