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Unformatted text preview: endothermic reaction. Standard Molar Enthalpies of Formation, ∆ H f o Example 15-6: Calculate the enthalpy change for the reaction in which 15.0 g of aluminum reacts with oxygen to form Al 2 O 3 at 25 o C and one atmosphere. 4 Al (s) + 3 O 2(g) → 2 Al 2 O 3(s) from Appendix K DH f o for Al 2 O 3 = - 1676 kJ/mol Hess’s Law Hess’s Law of Heat Summation states that the enthalpy change for a reaction is the same whether it occurs by one step or by any (hypothetical) series of steps. Hess’s Law is true because ∆ H is a state function. Hess’s Law If we know the following ∆ H o ’s...
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This note was uploaded on 12/08/2011 for the course CHEM 1211 taught by Professor Atwood during the Fall '07 term at University of Georgia Athens.
- Fall '07