AP Chem Unit 6 Thermochemistry

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What is thermochemistry?

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Thermochemistry is the study of the heat energy associated with chemical reactions and changes of state.

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Define endothermic process.

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An endothermic process is a reaction or change that absorbs heat from the surroundings.

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What is an exothermic process?

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An exothermic process is a reaction or change that releases heat to the surroundings.

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What is the standard enthalpy change of formation?

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The standard enthalpy change of formation is the change in enthalpy when one mole of a compound is formed from its elements in their standard states.

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How do you calculate the standard enthalpy change of formation of methane?

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Use Hess's law: ΔH_f = ΔH_combustion of products - ΔH_combustion of reactants.

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What is the significance of the activated complex in a reaction?

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The activated complex is a transient state during a chemical reaction where reactants are in a high-energy state before forming products.

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What is the energy of activation?

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The energy of activation is the minimum energy required for a chemical reaction to occur.

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How is energy required to produce chlorine calculated from a reaction?

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Divide the total energy change by the number of moles of chlorine produced.

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What does a negative enthalpy change indicate?

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A negative enthalpy change indicates that a reaction is exothermic.

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What does a positive enthalpy change indicate?

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A positive enthalpy change indicates that a reaction is endothermic.