We’re being asked to determine the **ΔG˚_{rxn}** at

C_{diamond }→ C_{graphite}

We’re given the **ΔH˚ _{f} and S˚** of each reactant and product.

Substance | H°_{f} (kJ/mol) | S° (J/mol•K) |

C_{graphite} | 0 | 5.740 |

C_{diamond} | 1.897 | 2.38 |

We can use the following equation to solve for ** ΔG˚_{rxn}**:

$\overline{){\mathbf{\Delta G}}{{\mathbf{\xb0}}}_{{\mathbf{rxn}}}{\mathbf{=}}{\mathbf{\Delta H}}{{\mathbf{\xb0}}}_{{\mathbf{rxn}}}{\mathbf{-}}{\mathbf{T\Delta S}}{{\mathbf{\xb0}}}_{{\mathbf{rxn}}}}$

For this problem, we need to do the following steps:

*Step 1:* Calculate ΔH˚_{rxn}.

*Step 2:* Calculate ΔS˚_{rxn}.

*Step 3:* Use ΔH˚_{rxn} and ΔS˚_{rxn} to calculate for ΔG˚_{rxn}.

What is the standard Gibbs free energy for the transformation of diamond to graphite at 298 K?

Elemental carbon usually exists in one of two forms: graphite or diamond. It is generally believed that diamonds last forever. Here are the standard enthalpy of formation (Δ*H°*_{f}) and the standard molar entropy (*S°*) values for diamond and graphite.

Substance | H°_{f} (kJ/mol) | S° (J/mol•K) |

C_{graphite} | 0 | 5.740 |

C_{diamond} | 1.897 | 2.38 |

Frequently Asked Questions

What scientific concept do you need to know in order to solve this problem?

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