CHE 101 Chapter Notes - Chapter 5: Calorie, Granola, Carbohydrate
8 Oct 2016
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Jim atwood: definitions (p 164 - 181) Chemical reactions are accompanied by energy changes: conservation of energy - energy is neither created nor destroyed, processes that liberate heat are exothermic, processes that absorb heat are endothermic c. i. Ex: cold pack: enthalpy h is the heat content of a substance d. i. State function: the enthalpy change for a reaction (at constant pressure) is our focus e. i. e. ii. Hrxn is negative for exothermic and positive for endothermic processes. 2 moles of h2(g) reacting with 1 mole o2(g) released. 4 moles h2(g) reacting with 2 moles o2(g) gives 967. 2 kj. *** change depend on amount: for the reverse reaction, the sign of hrxn changes. Hrxn = 483. 6 kj: the value of hrx depends on the state of the reactants and products. Work: energy to move object against a force. E = q + w q is heat w is work: calorimetry.
