The standard enthalpies of combustion of ethyne [C2 H2(g)], C(s), and H2(g) are -1299.6,-393.5,

step 1 To answer this question, to determine the standard enthalpy of f -thine, we need to know what ch

The standard enthalpies of combustion of ethyne [C2 H2(g)],...

The standard enthalpies of combustion of ethyne $\left[\mathrm{C}_{2} \mathrm{H}_{2}(g)\right], \mathrm{C}(s),$ and $\mathrm{H}_{2}(g)$ are $-1299.6,-393.5,$ and $-285.9 \mathrm{kJ} / \mathrm{mol},$ respectively. Use this information to calculate the standard enthalpy of formation of ethyne.

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Key Concepts

Standard Enthalpy of Formation

This is the heat change that occurs when one mole of a compound is formed from its constituent elements in their standard states. It is a fundamental concept used to understand and calculate the energy changes involved in chemical reactions, and it serves as a benchmark for comparing the stability and reactivity of compounds.

Standard Enthalpy of Combustion

This concept refers to the energy released as heat when one mole of a substance burns completely in oxygen under standard conditions. It is an important parameter in energy analysis and is used to determine the efficiency of fuels and the energy changes during combustion reactions.

Hess's Law

Hess's Law states that the total enthalpy change of a reaction is the same regardless of the pathway by which the reaction occurs. This principle allows for the calculation of unknown enthalpy changes, such as the standard enthalpy of formation, by combining or subtracting known enthalpy changes from related reactions.

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