Use the data in Appendix B to find standard enthalpies of reaction in kilojoules for the following processes: (a) C(s) + CO2(g) → 2 CO(g)

Verified step by step guidance

1. Identify the standard enthalpy of formation (ΔH_f^°) for each substance involved in the reaction from Appendix B.
2. Write the balanced chemical equation for the reaction: C(s) + CO_2(g) → 2 CO(g).
3. Use the formula for the standard enthalpy change of the reaction: ΔH_rxn^° = Σ ΔH_f^°(products) - Σ ΔH_f^°(reactants).
4. Substitute the standard enthalpies of formation for each substance into the formula: ΔH_rxn^° = [2 * ΔH_f^°(CO(g))] - [ΔH_f^°(C(s)) + ΔH_f^°(CO_2(g))].
5. Calculate the standard enthalpy change of the reaction using the values from Appendix B.

Key Concepts

Standard Enthalpy of Reaction

The standard enthalpy of reaction (ΔH°) is the heat change that occurs when a reaction takes place under standard conditions (1 atm pressure and a specified temperature, usually 25°C). It is measured in kilojoules per mole and indicates whether a reaction is exothermic (releases heat) or endothermic (absorbs heat). This value is crucial for predicting the energy changes associated with chemical reactions.

Hess's Law

Hess's Law states that the total enthalpy change for a reaction is the same, regardless of the number of steps the reaction takes. This principle allows chemists to calculate the enthalpy change for complex reactions by summing the enthalpy changes of individual steps, making it easier to find ΔH° for reactions that are difficult to measure directly.

Formation Reactions

A formation reaction is a specific type of reaction that produces one mole of a compound from its elements in their standard states. The standard enthalpy of formation (ΔHf°) is the change in enthalpy when one mole of a compound is formed from its elements. This concept is essential for calculating the standard enthalpy of reaction using the enthalpies of formation of the reactants and products.