### Practice Exercise 2Carbon occurs in two forms, graphite and diamond. The enthalpy of the combustion of graphite is \( -393.5 \, \text{kJ/mol} \), and that of diamond is \( -395.4 \, \text{kJ/mol} \):\[ \text{C(graphite)} + \text{O}_2(g) \rightarrow \text{CO}_2(g) \quad \Delta H = -393.5 \, \text{kJ} \]\[ \text{C(diamond)} + \text{O}_2(g) \rightarrow \text{CO}_2(g) \quad \Delta H = -395.4 \, \text{kJ} \]Calculate \(\Delta H\) for the conversion of graphite to diamond:\[ \text{C(graphite)} \rightarrow \text{C(diamond)} \quad \Delta H = \, ? \]

The given reaction schemes are: Cgraphite+O2g→CO2g ∆H=-393.5 kJ (i)Cdiamond+O2g→CO2g ∆H=-395.4 kJ (ii) Reverse the (ii) reaction. CO2g→Cdiamond+O2g ∆H=+395.4 kJ (iii)Add (i) and (iii) reaction. Cgraphite+O2g→CO2g ∆H=-393.5 kJ (i) CO2g→Cdiamond+O2g ∆H=+395.4 kJ (iii)Cgraphite→Cdiamond ∆H=+1.9 kJ¯ Thus, the ∆H for the conversion of graphite to diamond is +1.9 kJ/mol.

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Chemistry

- Practice Exercise 2 Carbon occurs in two forms, graphite and diamond. The en- thalpy of the combustion of graphite is -393.5 kJ/mol, and that of diamond is –395.4 kJ / mol: C(graphite) + O2(8) → CO2(8) AH = -393.5 kJ %3D C(diamond) + O2(8) – CO2(8) AH = -395.4 kJ > %3D Calculate AH for the conversion of graphite to diamond: C(graphite) C(diamond) AH = ?

- Practice Exercise 2 Carbon occurs in two forms, graphite and diamond. The en- thalpy of the combustion of graphite is -393.5 kJ/mol, and that of diamond is –395.4 kJ / mol: C(graphite) + O2(8) → CO2(8) AH = -393.5 kJ %3D C(diamond) + O2(8) – CO2(8) AH = -395.4 kJ > %3D Calculate AH for the conversion of graphite to diamond: C(graphite) C(diamond) AH = ?

Chemistry

10th Edition

ISBN:9781305957404

Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Publisher:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Chapter1: Chemical Foundations

Section: Chapter Questions

Problem 1RQ: Define and explain the differences between the following terms. a. law and theory b. theory and...

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