3. Using standard enthalpies of formation (∆Hfº), calculate the enthalpy change for the following reaction: 2H2S(g) + 3O2(g) → 2H2O(l) + 2SO2(g)                               ∆Hrxn = ?   ΔHf H2S (g) = -39.0 kJ/mol ΔHf O2 (g) = 0.0 kJ/mol ΔHf H2O (l) = -285.8 kJ/mol ΔHf SO2 (g) = -296.8 kJ/mol

A chemist measures the enthalpy change AH during the following reaction: P4(s) + 6 Cl,(g)→4 PCI3(g) AH=-1148. kJ Use this information to complete the table below. Round each of your answers to the nearest kJ/mol. reaction ΔΗ 2 1 -P -PCl, (g) s) + Cl, (g) kJ 3 4PCI, (g) - P, (s) + 6Cl, (g) | kJ 1 3 (s) + 4 Cl, (g) PCI, (g) kJ

When 3.50 g of Ba(s) is added to 100.00 g of water in a container open to the atmosphere, the reaction shown below occurs and the temperature of the resulting solution rises from 22.00°C to 47.40°C. If the specific heat of the solution is 4.18 J/(g ⋅ °C), calculate ΔH for the reaction, as written. Ba(s) + 2 H2O(l) → Ba(OH)2(aq) + H2(g)       ΔH = ?

Given the following thermochemical equations:H2 (g) + F2 (g) → 2HF (g) ΔH = -537 kJC (s) + 2F2 (g) → CF4 (g) ΔH = -680 kJ2C (s) + 2H2 (g) → C2H4 (g) ΔH = +52.3 kJCalculate the ΔH for the reaction of ethylene with F2: C2H4 (g) + 6F2 (g) → 2CF4 (g) + 4HF (g) [Calorimetry]

Using standard heats of formation (∆Hfo), calculate ∆H for the following reactions:  7O2(g) + 4NH3(g) → 4NO2(g) + 6H2O(l) CaCO3(s) → CaO(s) + CO2(g)

Use the following information to determine the enthalpy for the reaction shown below. CHĄ(g) + H20(g) → CO(g) + 3H2(g) AH° = ? 2C(s) + 2H20(g) → CHĄ(g) + CO2(g) AH° = 15.3 kJ C(s) + H20(g) → CO(g) + H2(g) CO(g) + H2O(g) –→ CO2(g) + H2(g) AH° = 131.3 kJ AH° = -41.2 kJ -206.1 kJ +206.1 kJ -74.8 kJ +74.8 kJ +149.6 kJ

A chemical reaction takes place in an open flask. The reaction releases 355 kJ of heat and does 25 kJ of work on the surroundings. Is the reaction endothermic or exothermic? Calculate ΔH for the reaction. Calculate ΔU for the reaction.

Using the following thermochemical equations; (a) CaO (s) + Cl2 (g) → CaOCl2 (s) ΔH°= -110.9 kJ(b) CaO (s) + H2O (l) → Ca(OH)2 (s) ΔH°= -65.1 kJ(c) H2O (l) + CaOCl2 (s) + Br2 (l) → Ca(OH)2 (s) + Br2 (l) +2 NaCl (s) ΔH°= -60.2 kJDetermine the value of ΔH° in kJ for the following reaction:½ Cl2 (g) + NaBr (s) → ½ Br2 (l) + NaCl (s)

The enthalpy change for the following reaction is given below. Pb (s) + CO2 (g) → PbO (s) + CO (g) ΔH° = +131.4 kJ Using the standard enthalpies of formation (∆Hf°) of CO2(g) = −393.5 kJ/mol, and CO(g) = −110.5 kJ/mol, determine the standard enthalpy of formation of PbO(s) A. −151.6 kJ ∕ mol B. −283.0 kJ ∕ mol C. +283.0 kJ ∕ mol D. −372.6 kJ ∕ mol E. +252.1 kJ ∕ mol

（1）Consider the reaction: 2A (g) + 3 B (g) → 2 C (g)     ΔHrxn = +254.3 kJ What will be the enthalpy change (in kJ) if 0.471 mol B reacts in excess A?   （2）Consider the reaction: C (s) + O2 (g) → CO2 (g)     ΔHrxn = -393.5 kJ What mass of carbon (in g) must be reacted via this mechanism to release 581.2 kJ of heat?