Densities of diamond and graphite are and respectively. For the transformation , . Which of the foll — Chemical Equilibrium Chemistry Question
Question
Densities of diamond and graphite are $3.5\text{ g/mL}$ and $2.3\text{ g/mL}$ respectively. For the transformation $C(\text{diamond}) \rightleftharpoons C(\text{graphite})$, $\Delta_r H = -1.9\text{ kJ/mol}$. Which of the following are favorable conditions for the formation of diamond?
💡 Solution & Explanation
The formation of graphite from diamond is exothermic ($\Delta H = -1.9\text{ kJ/mol}$), meaning the reverse reaction (forming diamond) is endothermic. Thus, high temperature favors diamond formation. Diamond ($3.5\text{ g/mL}$) is denser than graphite ($2.3\text{ g/mL}$), meaning it has a smaller volume. By Le-Chatelier's principle, high pressure shifts the equilibrium towards the state with smaller volume, also favoring diamond.