Thermochemical equations
5. Given 2NO → N2 + O2 ∆H= -180.7 determine the enthalpy of the reverse reaction? Is the reverse reaction endothermic or exothermic?
6. Given H2 + F2 → 2HF ∆H= -537 kJ
a) How much heat is required to react 9.5 g F2 with H2?
b) What mass of H2 is needed to react with F2 with -294 kJ of energy?
Hess Law
State Hess’s Law
8. Use the standard reaction enthalpies given below to determine ΔH° for the following reaction:
2S(s) + 3O2(g) ---> 2SO3(g) ΔH°=?
|
SO2(g) ---> S(s) + O2(g) |
ΔH° = +296.8 kJ |
|
2SO2(g) + O2(g) ---> 2SO3(g) |
ΔH° = −197.8 kJ |
Given:


Thermochemical equations 5. Given 2NO → N2 + O2 ∆H= -180.7 determine the enthalpy of the...
Use the standard reaction enthalpies given below to determine ΔH°rxn for the following reaction: 4 SO3(g) → 4 S(s) + 6O2(g) ΔH°rxn = ? Given: SO2(g) → S(s) +O2(E) ΔH°rxn = +296.8 kJ 2 SO2(g) + O2(g) → 2SO3(g) ΔH°rxn = -197.8 kJ-494.6 kJ -692.4 kJ -791.4 kJ 1583 kJ 293.0 kJ
Given the following reactions N2 (g) + O2 (g) → 2NO (g) ΔH = +180.7 kJ 2N2O (g) → O2 (g) + 2N2 (g) ΔH = -163.2 kJ the enthalpy of reaction for 2N2O (g) → 2NO (g) + N2 (g) is ________ kJ.
Part A Calculate the enthalpy of the reaction 2NO(g)+O2(g)→2NO2(g) given the following reactions and enthalpies of formation: 12N2(g)+O2(g)→NO2(g), ΔH∘A=33.2 kJ 12N2(g)+12O2(g)→NO(g), ΔH∘B=90.2 kJ Express your answer with the appropriate units. Part B Calculate the enthalpy of the reaction 4B(s)+3O2(g)→2B2O3(s) given the following pertinent information: B2O3(s)+3H2O(g)→3O2(g)+B2H6(g), ΔH∘A=+2035 kJ 2B(s)+3H2(g)→B2H6(g), ΔH∘B=+36 kJ H2(g)+12O2(g)→H2O(l), ΔH∘C=−285 kJ H2O(l)→H2O(g), ΔH∘D=+44 kJ Express your answer with the appropriate units.
Given the following reactions N2 (g) + O2 (g) → 2NO (g) ΔH = +180.7 kJ 2NO( g) + O2 (g) → 2NO2 (g) ΔH = -113.1 kJ the enthalpy for the decomposition of nitrogen dioxide into molecular nitrogen and oxygen 2NO2 (g) → N2 (g) + 2O2 (g) is ________ kJ.
Calculate the standard enthalpy change, ΔH°rxn, in kJ for the following chemical equation, using only the thermochemical equations below: 2H2S(g) + 4O2(g) → 2SO3(g) + 2H2O(l) Report your answer to three significant figures in scientific notation. Equations: ΔH°rxn (kJ) 2S(s) + 3O2(g) → 2SO3(g) -790.4 S(s) + O2(g) → SO2(g) -296.9 2H2S(g) + 3O2(g) → 2SO2(g) + 2H2O(l) -1125.1
Given: C(s) + O2(g) ---> CO2(g) ΔH = −393.5 kJ/mol S(s) + O2(g) ---> SO2(g) ΔH = −296.8 kJ/mol C(s) + 2S(s) ---> CS2(ℓ) ΔH = +87.9 kJ/mol A) Calculate the standard enthalpy change for the following reaction CS2(ℓ) + 3O2(g) ---> CO2(g) + 2SO2(g) ΔH° rxn = -1075 kJ/mol B) Using the equation and standard enthalpy change for the reaction (from part A), calculate the amount of heat produced or consumed when 3.2 mol of CS2 reacts with excess...
2. Use Hess’s Law to determine the enthalpy of the reaction below. 2F2(g) + 2H2O(l) → 4HF(aq) + O2(g) DH˚= ? H2(g) + F2(g) → 2HF(aq) DH˚ = -546.6 kJ 2H2 (g) + O2(g) → 2H2O(l) DH˚ = -571.6 kJ a. 42 kJ b. -1120 kJ c. -251 kJ d. -521 kJ e. -1690 kJ
Given the thermochemical equation for the formation of H2O by burning H2 and O2: H2(g) + 402 (8) → H2O (8) ΔH° = -241.8 kJ Calculate the ΔH for the following reaction: 2H2O (g) → 2 H2(g) + O2 (g)
(10) 5. Use the given reactions and their enthalpies to determine the AHºrxn for the following reaction: 2 S(x) + 3 O2(g) → 2503(g) Hºrxn - ? Given Reactions and their Standard Enthalpies of Reaction: SO2(g) - S(s) + O2(g) 2 SO2(g) + O2(g) 2 S03(g) AHºrxn = +296.8 kJ Hºrxn = -197.8 kJ (10) 6. Use standard enthalpies of formation (AH°f) to determine AHºrxn for the reaction below. 2 CH3OH(1) + 3 02(g) → 2 CO2(g) + 4H2O(g)
a) Calculate the enthalpy of the reaction 2NO(g)+O2(g)→2NO2(g) given the following reactions and enthalpies of formation: 12N2(g)+O2(g)→NO2(g), ΔfH∘A=33.2 kJ mol−1 12N2(g)+12O2(g)→NO(g), ΔfH∘B=90.2 kJ mol−1 Express your answer with the appropriate units. b) Calculate the enthalpy of the reaction 4B(s)+3O2(g)→2B2O3(s) given the following pertinent information: B2O3(s)+3H2O(g)→3O2(g)+B2H6(g), ΔrH∘A=+2035 kJ mol−1 2B(s)+3H2(g)→B2H6(g), ΔrH∘B=+36 kJ mol−1 H2(g)+12O2(g)→H2O(l), ΔrH∘C=−285 kJ mol−1 H2O(l)→H2O(g), ΔrH∘D=+44 kJ mol−1