According to advertisements, “a diamond is forever.”

(a) Calculate $\Delta H^{\circ}, \Delta S^{\circ},$ and $\Delta G^{\circ}$ at 298 $\mathrm{K}$ for the phase change

(b) Given the conditions under which diamond jewelry is normally kept, argue for and against the statement in the ad.

(c) Given the answers in part (a), what would need to be done to make synthetic diamonds from graphite?

(d) Assuming $\Delta H^{\circ}$ and $\Delta S^{\circ}$ do not change with temperature, can graphite be converted to diamond spontaneously at 1 $\mathrm{atm} ?$

## Discussion

## Video Transcript

No transcript available

## Recommended Questions

The “filmstrip” represents five molecular scenes of a gaseous mixture as it reaches equilibrium over time:

$\mathrm{X}$ is purple and $\mathrm{Y}$ is orange: $\mathrm{X}_{2}(g)+\mathrm{Y}_{2}(g) \rightleftharpoons 2 \mathrm{XY}(g)$

(a) Write the reaction quotient, $Q,$ for this reaction.

(b) If each particle represents $0.1 \mathrm{mol},$ find $Q$ for each scene.

(c) If $K>1,$ is time progressing to the right or to the left? Explain.

(d) Calculate $K$ at this temperature.

(e) If $\Delta H_{\mathrm{rxn}}^{\circ}<0,$ which scene, if any, best represents the mixture at a higher temperature? Explain.

(f) Which scene, if any, best represents the mixture at a higher pressure (lower volume)? Explain.

A reaction $\mathrm{A}(g) \rightleftharpoons \mathrm{B}(g)$ has an equilibrium constant of

$1.0 \times 10^{-4} .$ For which of the initial reaction mixtures is the $x$ is small approximation most likely to apply?

$$

\begin{array}{l}{\text { a. }[\mathrm{A}]=0.0010 \mathrm{M} ;[\mathrm{B}]=0.00 \mathrm{M}} \\ {\text { b. }[\mathrm{A}]=0.00 \mathrm{M} ;[\mathrm{B}]=0.10 \mathrm{M}} \\ {\text { c. }[\mathrm{A}]=0.10 \mathrm{M} ;[\mathrm{B}]=0.10 \mathrm{M}} \\ {\text { d. }[\mathrm{A}]=0.10 \mathrm{M} ;[\mathrm{B}]=0.00 \mathrm{M}}\end{array}

$$