Standard state 25 c and one atmosphere of pressure

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Standard state 25° C and one atmosphere of pressure Std. state form? H O O (diatomic molecule) N C Cl 2( ) Cl 2(g) (diatomic molecule) I H H ( t lli lid) Hg Hg (metallic solid) S S. Ensign, thermochemistry 53 Standard enthalpies of formation for selected compounds at 298.15 K (25 ° ) Tabulated enthalpies of formation ( Δ H f °) Substance H ° f (kJ/mol) Substance H ° f (kJ/mol) CO 2 (g) -393.5 NH 3 (g) -46.19 CH 4 (g) -74.8 NaCl(s) -410.9 74.8 410.9 C 6 H 12 O 6 (s) -1273 C(s) diamond 1.88 CH 3 OH(l) -238.6 H 2 O(g) -241.8 C 2 H 2 (g) 226 7 H 2 O(l) -285 85 (g) 226.7 O(l) 285.85 Δ H f ° for an element in it’s standard state = 0 S. Ensign, thermochemistry 54 Using a table of enthalpies of formation to calculate the enthalpy change ( Δ H°) for a H ) for a chemical reaction of interest Δ rxn = Σ n Δ H f °(products) - Σ m Δ H f °(reactants) Appropriate stoichiometric coefficients in the balanced chemical equation Standard enthalpies of formation for selected compounds at 298.15 K (25 ° ) Substance H ° f (kJ/mol) Substance H ° f (kJ/mol) CO 2 (g) -393.5 NH 3 (g) -46.19 CH 4 (g) -74.8 NaCl(s) -410.9 C 6 H 12 O 6 (s) -1273 C(s) diamond 1.88 CH 3 OH(l) -238.6 H 2 O(g) -241.8 S. Ensign, thermochemistry 55 C 2 H 2 (g) 226.7 H 2 O(l) -285.85 What enthalpy change is associated with the production of glucose and oxygen from carbon dioxide and water (the reaction of photosynthesis)? 6CO 2(g) + 6H 2 O (l) Æ C 6 H 12 O 6(s) + 6O 2(g) 6H 6O S. Ensign, thermochemistry 56
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What enthalpy change is associated with the production of glucose and oxygen from carbon dioxide and water (the reaction of photosynthesis)? 6CO 2(g) + 6H 2 O (l) Æ C 6 H 12 O 6(s) + 6O 2(g) Standard enthalpies of formation for selected compounds at 298.15 K (25 ° ) Substance H ° f (kJ/mol) Substance H ° f (kJ/mol) CO 2 (g) -393.5 NH 3 (g) -46.19 CH 4 (g) -74.8 NaCl(s) -410.9 C 6 H 12 O 6 (s) -1273 C(s) diamond 1.88 CH 3 OH(l) -238.6 H 2 O(g) -241.8 C 2 H 2 (g) 226.7 H 2 O(l) -285.85 Δ = Σ n Δ H °(products) Σ m Δ H °(reactants) S. Ensign, thermochemistry 57 H rxn = H f (products) - H f (reactants) What enthalpy change is associated with the production of glucose and oxygen from carbon dioxide and water (the reaction of photosynthesis)? 6CO 2(g) + 6H 2 O (l) Æ C 6 H 12 O 6(s) + 6O 2(g) Standard enthalpies of formation for selected compounds at 298.15 K (25 ° ) Δ rxn = Σ n Δ H f °(products) - Σ m Δ H f °(reactants) Substance H ° f (kJ/mol) Substance H ° f (kJ/mol) CO 2 (g) -393.5 NH 3 (g) -46.19 CH 4 (g) -74.8 NaCl(s) -410.9 C 6 H 12 O 6 (s) -1273 C(s) diamond 1.88 CH OH(l) -238 6 H O(g) -241 8 3 -238.6 2 O(g) -241.8 C 2 H 2 (g) 226.7 H 2 O(l) -285.85 S. Ensign, thermochemistry 58
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